HAIRAULT Jean Olivier

This thesis explores the implications of technical progress and labor taxation on employment performance in France and the United States over the past four decades. Chapter 1 assesses the extent to which differences in socio-demographic and occupational structures between countries explain the French employment deficit. This deficit reflects not only a deficient labor market, but also a reallocation of work that affects the employment prospects and participation decisions of specific sociodemographic groups. Chapter 2 examines the determinants of unskilled employment performance in France between 1982 and 2008. Technical progress and labor taxation policies are key to understanding the deterioration of unskilled employment. The reallocation of unskilled labor from routine jobs to manual jobs induced by technical progress is partly hindered by the presence of the non-market sector. Labor taxation interacts with technical progress by changing the value of unskilled jobs relative to non-market labor. Chapter 3 studies the implications of routine technology shocks on economic fluctuations between 1989 and 2017 in the United States. It assesses their impact by estimating a structural VAR model. Technology shocks biased against routine tasks explain the recessionary effects of technology shocks on hours worked. These shocks appear quantitatively relevant and generate recognizable business cycle fluctuations.

"Important non-financial firms debt levels in foreign currency have been achieved in many emerging countries. The consequences of important exchange rate depreciations raise concerns about the effects on the economy aggregate such an investment. This paper studies the role of exchange rate shocks in explaining debt dynamics in foreign currency for non-financial firms and the impact on the economy aggregates. The analysis is based in a DSGE model inspired on the work of Mendoza (2010). We showed that exchange rate appreciation periods diminish the probability of having a financial crisis, and is correlated with higher leverage in the economy for the firms. We also showed that fluctuations of economy aggegates are amplified when there is a depreciation of the exchange rate and reduced it during exchange rate appreciation periods.

In this paper, we show that (i) the volatility of worker flows increases with age in US CPS data, and (ii)a search and matching model with life-cycle features, endogenous separation and search effort, is well suited to explain this fact. With a shorter horizon on the labor market, older workers’ outside options become less responsive to new employment opportunities, thereby making their wages less sensitive to the business cycle. Their job finding and separation rates are then more volatile along the business cycle. The horizon effect cannot explain the significant differences between prime-age and young workers as both age groups are far away from retirement. A lower bargaining power on the youth labor market brings the model closer to the data.

This doctoral dissertation focuses on wealth inequality through the prism of two markets: the marriage market (chapter 1) and the labor market (chapters 2 and 3). In the first chapter, Normann Rion and I analyze the role of marriage, and more specifically of financial endogamy, in the formation of the high wealth inequalities observed in the United States. We use a dynamic life cycle model where each agent rationally chooses his or her spouse. This model predicts that a decrease in the marriage rate reduces inequality while an increase in endogamy increases the wealth gap between Americans. In the second chapter, we analyze not the sources but the consequences of wealth inequality, again in the United States where inequality is at its highest. In particular, we propose a link between the low wealth of young people (aged 21 to 30) and their wage trajectory following episodes of involuntary job loss. Indeed, the after-effects of youth unemployment are significant, which seems a priori inconsistent with the predictions of existing labor market models. Our contribution is to show that an explanation based on a career choice under a financial constraint is theoretically and empirically plausible. The third chapter, co-authored with Cem Ozguzel, is purely empirical. We revisit the very fact that young people suffer significantly from job losses, using German administrative data. The age profile of the cost of unemployment that we obtain for Germany is comparable to that documented in the literature on the United States.

In this paper, we show that (i) the volatility of worker flows increases with age in US CPS data, and (ii) a search and matching model with life-cycle features, endogenous separation and search effort, is well suited to explain this fact. With a shorter horizon on the labor market, older workers' outside options become less responsive to new employment opportunities, thereby making their wages less sensitive to the business cycle. Their job finding and separation rates are then more volatile along the business cycle. The horizon effect cannot explain the significant differences between prime-age and young workers as both age groups are far away from retirement. A lower bargaining power on the youth labor market brings the model closer to the data. JEL Classification: E32, J11, J23.

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In this paper, we aim to establish some stylized facts about the relative contributions of the job-finding and separation rates to unemployment dynamics depending on the nature of structural shocks. The shocks in our Bayesian Structural VAR model are identified using a sign-restriction approach, and capture shifts in the three conditions determining labor-market equilibrium in matching models: the Beveridge curve, and the job-creation and job-destruction conditions. Using both US and French data, we identify an aggregate shock to match profitability (the aggregate-profitability shock), a shock specific to existing jobs (the reallocation shock) and a shock to the efficiency of the matching process (the matching-efficiency shock). We find that the relative contributions of the job finding and separation rates are notably different across shocks in both countries, but are similar across countries for each type of shock. Labor market dynamics appear to be Transatlantic despite well-known institutional differences. However, it must be emphasized that the reaction of the labor market variables to the matching-efficiency shock seems more muted in the US than in France.

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During my dissertation, I conducted applied macroeconomic research on a variety of topics, ranging from the effects of job polarization on worker reallocation to the effects of monetary policy on firm capital structure and financial decisions. This thesis collects three papers on these arguments. The main paper of the thesis is my job market paper. This work gave me the opportunity to explore in detail the effects of technological change on the occupational structure of labor markets, but also its effects on the reallocation of workers between jobs and the process of sorting skills into jobs. In other words, the paper answers these questions: how do workers use the occupational ladder when technological innovation changes its structure? What are their job opportunities, given their skills, when technology changes? And what skills are employers looking for? This argument has always intrigued me, and its relevance is currently attracting the attention of governments and policymakers in many developed economies. My research departs from these facts to analyze what the effects of technological change are on workers and firms. In particular, it shows - as has already been documented in the literature on job polarization - that technological innovation reshapes the occupational structure of the economy by destroying certain types of jobs. However, I show that technological innovation changes the demand for skills in each occupation in ways that have heterogeneous effects on workers in terms of labor mobility, job opportunities, and matching quality. In particular, this paper is the first to show that technology - by causing labor market polarization - triggers large movements from the top to the bottom of the job ladder, with many workers ending up in lower-paying, lower-skilled occupations. The effects of technological change on labor market outcomes and dynamics are also examined in the second chapter of this thesis. In particular, this work, in collaboration with Joanne Tan, shows how technological change can explain the increase in occupational shortage and how different segments of the labor market respond to it In the final chapter of the thesis, I focus on the relationship between monetary policy and the stock buyback decision. This topic is unrelated to the previous one, but I have always been interested in how macro-variables can influence managers' decisions at the micro level. In this work, jointly with Assia Elgouacem, we use firm-level data and show that US firms buy back more of their own shares during periods of accommodative monetary policy, i.e. when the cost of debt is low. In fact, we show that if a firm's yield curve adjusts in the direction expected by monetary policy, i.e., the cost of debt decreases, the firm will issue more bonds to raise funds at lower cost. However, they will use most of this new cash to fund a buyback program rather than invest in new capital and jobs. This crowding out effect of buybacks on new investment and employment is questionable because it dampens the transmission of monetary policy.

This volume examines the interaction of labour market conditions and retirement decisions. Based on French and US data, it provides empirical evidence and quantitative analysis of retirement and labor market flows. It studies the horizon effect and uses French individual data and probit models to show that the horizon effect does matter for the probability of being employed before the early retirement age. It analyses the influence of the retirement age on labour-market equilibrium, as well as the impact of labour market conditions, especially the importance of unemployment risk, on retirement decisions.

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The underlying objective of the three chapters that make up this thesis is to understand the functioning of the labor market in order to establish a diagnosis of the potential regulatory role of a public authority in this market. In the first chapter, I analyze, from a purely "positive" point of view, the ability of the model with matching frictions to replicate short term fluctuations of labor market variables in the United States. I propose a new calibration strategy, in the framework of a model of fluctuations with price rigidity. In the second chapter (co-authored with F. Langot), we study the determinants of labor supply changes over the last fifty years. The evolution of the tax wedge, as well as of two variables reflecting the institutional framework (the generosity of income in case of "non-employment" and the bargaining power of workers), help explain the different trajectories of the employment rate and hours worked observed in the United States and in three European economies (France, Germany and the United Kingdom). In the third chapter, I analyze the performance of two alternative social security systems in a model with wealth heterogeneous agents. Agents are subject to the risk of unemployment, and the planner can provide insurance through a redistributive tax system, based on a progressive tax and/or unemployment insurance. The progressive tax system is superior, in terms of aggregate welfare, to the insurance provided through unemployment benefits, through its effect on the functioning of the labor market.

In this paper, we extend our previous analysis (Albertini, Hairault, Langot and Sopraseuth (2015)) along two dimensions. Firstly, we introduce an endogenous number of firms à la Melitz (2003) in order to account for interactions between good and labor markets, and their respective institutions. Secondly, rather than focusing on the historical path of ou prototypical economies as in the previous paper we now want to forecast their future dynamics as spurred by large changes in technology. Hence, for each economy we analyze the transitional dynamics from today to a new world, i.e. the path along which structural technological changes remove the competitive advantages of workers in the middle of the wage distribution, leading them to move to new opportunities at the bottom of the wage distribution. By nature, this phenomenon takes time (searching for a job in a new occupation is time consuming), and it can be blocked if redistributive policies, by increasing the outside option of the poorest, cancel the potential profits of new jobs in the service sector.3 Beyond he comparison of the initial and final steady states, we also solve the transitional dynamics. Further, our paper goes beyond the traditional analysis of PMR and LMIs’ effects on labor market outcomes by focusing on their effects on the reallocation from routine to manual tasks.

The objective underlying the three chapters that make up this thesis is to better understand the impact of public policies whose impacts differ across heterogeneous sectors. We apply this analysis to three types of public policies at the heart of contemporary macroeconomics: (i) environmental policy, (ii) development aid policy and (iii) twin deficit policy. Through these three chapters, we argue that the sectoral impacts of policies play a crucial role in the evaluation of policies and in the determination of the optimal policy. The first chapter focuses on the pollution tax. It provides a theoretical model that explains why there is a negative relationship between household income and their support for the pollution tax. In the second chapter, I study the macroeconomic impacts of a development aid policy and consider two sectors: the tradable goods sector (T-sector) and the non-tradable goods sector (N-sector). I consider two types of foreign aid: (i) aid distributed through lump sum transfers to households and (ii) aid to finance public investments. I study the impact of capital market liberalization on the optimal form and performance of development aid. The third chapter focuses on twin deficits: a current account deficit induced by a balanced budget deficit. The econometric analysis of the paper shows that countries with centralized wage bargaining have smaller twin deficits than others. This chapter also provides a theoretical model to explain these empirical results.

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We first propose some new empirical evidence on the fact that the labor market conditions matter for the retirement decision at the individual level: we investigate whether unemployed workers retire before employed workers, other things being equal. Our main objective in this paper is then to propose an equilibrium unemployment approach to retirement decisions that allows us to derive the positive and normative features of retirement decisions when search and matching frictions are considered. Two main conclusions emerge: the retirement decision of unemployed workers depends on the labor-market frictions whereas that of employed workers does not. the existence of search externalities makes the retirement age of unemployed workers intrinsically suboptimal. Considering Social Security policy issues, we show that the complete elimination of the implicit tax on continued activity is not necessarily welfare-optimizing in a second best world where the labor market equilibrium suffers from distortions.

This thesis aims to explain three major economic facts: excessive urban sprawl, unemployment dispersion, and trade hierarchy. In the first chapter, I construct and calibrate a simple labor market matching model in which the residential density of workers is endogenous. Using this analytical framework I show that the structure of the labor market creates significant excess sprawl. I identify the fact that firms compensate for the transportation costs of employees as the major source of this inefficiency. Finally, I point out that optimality can be restored if the government implements mileage compensation. The second chapter questions the fact that although it has been established that cities are characterized by a high dispersion of unemployment, segregation models remain the standard framework of urban and labor economics. In particular, I show that the classical model of this literature explains the dispersion of unemployment if the residential environment affects workers' preferences. In the third chapter, co-authored with Antoine Vatan, we show that whether firms follow a trade hierarchy depends very strongly on their experience as exporters. Then, we develop a simple and dynamic model that addresses the new empirical fact that we have highlighted. Namely, we show that this new fact can be explained by a trade-off between attractiveness and competition, the latter being present in any model of monopolistic competition with sequential exporting.

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Once considered an example on a global scale, the French social model is now out of breath. Working hours are decreasing, early retirement has been encouraged for a long time, entire sectors of industry are gradually disappearing, the creation of low-skilled jobs has been refused because they are considered "indecent", and the system of subsidies has had perverse effects: by wanting to avoid unemployment at all costs, France has chosen to be inactive. In the end, it has reaped both. According to Jean-Olivier Hairault, economist and associate researcher at CEPREMAP (Center for Economic Research), a new social model must be redefined. By sacrificing the illusory ideological equality to dare a necessary pragmatism. By working harder to reduce taxes and public debt while preserving a high level of social protection. Only then will France prove to itself that it is both protective and competitive.

Since the last recession, it is usually argued that older workers are less affected by the economic downturn because their unemployment rate rose less than the one of prime-age workers. This view is a myth: older workers are more sensitive to the business cycle. We document volatilities of worker flows and hourly wage across age groups on CPS data. We find that old worker's job flows are characterized by a higher responsiveness to business cycles than their younger counterparts. In contrast, their wage cyclicality is lower than prime-age workers'. Beyond this empirical contribution, we show that a life-cycle Mortensen & Pissarides (1994) model is well suited to explain these facts: older workers' shorter work-life expectancy endogenously reduces their outside options and leads their wages to be less sensitive to the business cycle. Thus, in a market where wage adjustments are small, quantities vary a lot: this is the case for older workers, whereas the youngest behave like infinitively-lived agents. Our theoretical results point out that Shimer (2005)'s view on the MP model is consistent with prime-age workers' labor market while aging endogenously introduces real wage rigidities, allowing to match what we observe for old workers, without specific assumptions as in Hagendorn & Manovskii (2008).

The starting point of this thesis is related to Shimer's criticism, i.e. the inability of the matching model to reproduce the high volatility of the unemployment rate. The introduction of real wage rigidity was seen as the answer to this criticism. Nevertheless, Sveen and Weinke (2008) pointed out that this rigidity would have no effect on volatility when firms choose the number of hours worked per worker. In Chapter 1, we show that this result is related to the way wage rigidity is incorporated. We show that when wage rigidity is introduced by Hall and Milgrom's (2008) "credible bargaining", volatility is strongly amplified, even when firms choose the number of hours per worker. Moreover, a significant trade-off between inflation stabilization and unemployment stabilization is restored. In chapter 2, we point out that credible bargaining, however, produces only a moderate degree of wage rigidity and is only able to fully replicate unemployment volatility for unrealistic values of some parameters. We add an information asymmetry to this model. The resulting increase in wage rigidity allows us to replicate the volatility with a plausible calibration. Finally, we show that it is possible to solve the Shimer critique without resorting to wage rigidities, but by considering a particular calibration of the model with endogenous job destruction. We also highlight a central mechanism of this model, such that the volatility of the destruction rate amplifies the volatility of the return to employment rate.

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This paper extends the job creation--job destruction approach to the labor market to take into account a deterministic finite horizon. As hirings and separations depend on the time over which investment costs can be recouped, the life-cycle setting implies age-differentiated labor-market flows. While search by the unemployed falls with age, the separation rate is rather U-shaped over the life cycle. Worker heterogeneity in the context of undirected search implies an intergenerational externality, which is not eliminated by the Hosios condition. We show that age-specific policies are required to attain the first-best allocation.

At the end of working life, as well as reducing unemployment benefits, the unemployment-insurance agency could apply pension tax instead of wage tax. First, the pension tax provides greater incentives as the value of re-employment is tax-free. Second, the short job duration before retirement implies that the budgetary return and search incentives associated with the pension tax are considerable. By way of contrast, younger workers have greater search intensity and their future pension taxes are more remote and therefore more heavily-discounted: for them the wage tax is more efficient than is the pension tax. Finally, even in the special case where search intensity is zero close to retirement, perfect risk-sharing across unemployment and retirement is welfare-improving thanks to the pension tax.

This thesis focuses on the retirement decision. The four chapters that make up the thesis study the transition from employment to retirement. The first essay examines the determinants of this transition in the United States, where "retirement" means social security rather than termination of employment. Any worker can "liquidate" his or her social security rights at any age between 62 and 70, according to an almost actuarially neutral scale. In other words, the longer the individual postpones this decision, the higher the monthly pension will be, but for a shorter period. Insofar as the liquidation of social security rights before the normal age of eligibility has become the norm rather than the exception, it is legitimate to reflect on the incentives that push American seniors to make this decision. As they approach retirement age, many cash-strapped individuals turn to Social Security as a safety net to fund their standard of living during a financial slump. For the unemployed in particular, social security can play the role of unemployment insurance, allowing them to finance their consumption while they look for a new job, thus keeping them in the labor market longer. The rest of the thesis focuses on the relationship between subjective well-being and retirement. This relationship is important from a normative point of view in order to understand the distribution of well-being among individuals, but especially from a positive point of view because subjective well-being has consequences for work, and therefore for retirement.

The objective of this thesis is to study the role of employment and firm entry-exit flows in the dynamics of the business cycle. More specifically, this work aims to show the effects of these reallocation flows in the presence of frictions in the labor and capital markets. In the first chapter, written in collaboration with F. Pappadà, we highlight a new amplification channel associated with credit constraints. The theoretical model we propose predicts that the recession causes a more pronounced fall in aggregate output in the presence of credit constraints due to a higher rate of firm destruction. The second chapter focuses on the role of reallocation flows in the dynamics of aggregate productivity. Unlike the usual decompositions, the method we propose allows us to measure the contribution of changes in allocative efficiency. Estimated on French data over the period 1991-2006, this decomposition indicates that recessions contribute to improving aggregate productivity through an improvement in resource allocation. The last chapter, the result of a collaboration with J-Q Hairault and F. Langot, examines the consequences of economic fluctuations on the well-being of economic agents. In the presence of matching frictions, we show that economic fluctuations increase the average level of unemployment. Fluctuations are then costly, not only because of households' aversion to volatility, but also because of the indirect consequences of this volatility on the average level of consumption.

The objective of this thesis is twofold. First, we analyze the interaction between monetary and fiscal policy in a non-Ricardian framework where monetary policy is constrained by the positivity of nominal interest rates. Second, we study the implications of public debt on macroeconomic aggregates.

This doctoral dissertation analyzes optimal public debt in an economy where agents face idiosyncratic risk, credit constraints, and cannot perfectly insure themselves due to incomplete insurance markets. It extends the literature through three original contributions. The first chapter focuses on the determination of optimal debt in the presence of macroeconomic fluctuations. The second chapter introduces entrepreneurial households and analyzes their impact on the optimal debt level. The third and last chapter proposes to revisit the analysis of the optimal debt level in an economy where the government does not have a commitment technology. Through these three chapters, this thesis presents a set of ingredients and effects that contribute to a better understanding and definition of public debt policies.

The first chapter studies the implications of a nested generation model with transaction costs on international portfolio diversification. Our results show that the introduction of very small transaction costs makes it possible to reproduce the phenomenon of preference for domestic financial securities. The second chapter analyzes the relationship between the domestic stock preference phenomenon, financial analysts' forecasts and earnings opacity. Using high-quality portfolio composition data and introducing a higher-order moment estimator, we confirm, improve and generalize the recent results obtained by Ahearne et al. (2004). First, we show that the accuracy of financial analysts' forecasts can help explain the lack of diversification observed in the composition of US portfolios. Second, we highlight the relationship between opacity measures and the phenomenon of domestic stock preference. In the third chapter, we revisit the quantity puzzle by developing an international model of delegated management cycles. In each country, shareholders hire managers and delegate hiring and investment decisions to them. We show that managers make intertemporal decisions in their own interest, including investment decisions, which have important consequences on the quantity puzzle. The model replicates the main stylized facts of international fluctuations.

This thesis is based on the observation that precautionary saving, which results from incomplete insurance markets and a debt constraint (Aiyagari [1994]), is important. This mechanism is therefore likely to modify the impact of economic policies. The thesis project is then to integrate the precautionary savings mechanism into the evaluation of insurance and redistribution policies. The mechanism by which income and inheritance tax progressivities as they exist in France have reduced wealth inequality differs. The progressivity of the income tax reduces the savings of the richest, whereas the progressivity of the inheritance tax creates savings for the bequest motive for the poorest. When agents are able to save, the degressive unemployment benefit can reduce the conflict of objectives between efficiency and equity, unlike Cahuc and Lehmann [2000]. The existence of an aggregate risk that exacerbates individual income risk invites us to reconsider the optimal level of debt significantly upwards.

Numerous studies highlight the existence of substantial costs affecting international trade flows. By creating a segmentation of international markets, these trade barriers affect the global equilibrium in open macroeconomics. However, most macroeconomic models ignore this feature of the international economy and assume perfect market integration. The three parts that make up this thesis study the impact of this segmentation of international markets on macroeconomic equilibrium. The tools developed by the New Trade Theories are used to model the impact of trade barriers on the strategic decisions of firms in a globalized environment. The first part of the thesis focuses on the consequences of market segmentation on export pricing strategies. The empirical analysis highlights the microeconomic determinants that explain the low sensitivity of trade prices to exchange rate fluctuations. The second part introduces the analysis of firms' location choices and studies their impact on the level of relative prices. It shows how the entry of new producers into a national market exerts downward pressure on its aggregate price level. Finally, the third part of the thesis examines the impact of these location choices on the efficiency of economic policies. More precisely, it shows how national minimum wage policies affect the spatial distribution of firms, through the relative costs of production but also through their impact on aggregate demand.

The purpose of this thesis is to understand the transmission of income inequalities through inheritances. The aim is to identify the economic mechanisms of inequality persistence and to determine the dynamic interactions between the economic environment and the distribution of inheritances. We show that the combination of credit market imperfections and the unequal access of agents to different returns on capital is a driver of initial wealth inequality. In the presence of these two phenomena, the pay-as-you-go pension system worsens initial wealth inequality. We then show that the distribution of human capital is a powerful driver of inequality persistence independently of its links with financial wealth. Indeed, the existence of different profiles of returns to human capital in the economy and of heterogeneity in the opportunity costs of investment in human capital lead agents to have different comparative advantages in their choice of occupation. This mechanism thus explains the distribution of agents in the different occupations. At the macroeconomic level, it explains the impact of the distribution of human capital on growth. For example, we show that, when individuals with low levels of human capital have a comparative advantage to engage in imitation, only individuals with a relatively high level of human capital engage in growth-enhancing innovation. The growth rate of the economy thus depends on the fraction of individuals who engage in innovation and on the average level of human capital of these individuals.

The purpose of this thesis is to deepen our understanding of the role of financial factors in the French business cycle. In particular, it aims to study the importance of wealth effects for households and to test the existence of a credit channel for inventory investment. Chapter 1 begins with a review of the literature on inventories. It presents the main findings from theory and empirical studies on the determinants of macroeconomic fluctuations in inventories. Chapter 2 of the thesis is devoted to the estimation of an inventory equation on French aggregate data, with the objective of analyzing the role played by financing constraints in inventory investment decisions. In the next two chapters, stochastic intertemporal general equilibrium models incorporating inventories with a financial dimension are developed. In each case, the model is calibrated to the French economy. Chapter 3 of the thesis explores the role played by monetary shocks in the fluctuations of the French economy. In particular, the ability of the model to reproduce the inventory cycle is analyzed. Chapter 4 proposes a model incorporating a financial gas pedal mechanism on inventory investment. This model is able to reproduce a number of stylized facts when subjected to both technological and monetary impulses, and to evaluate the amplifying effect of financial factors on inventory behavior and on the product. The last chapter of the thesis is devoted to the analysis of the role of households' wealth in their consumption behavior.

Since the introduction of flexible exchange rates in 1971, the extreme volatility of real exchange rates in OECD countries has raised many questions. Adopting a theoretical approach within the framework of the New International Macroeconomics, the thesis proposes an explanation for the observed fluctuations of nominal and real exchange rates of the G7 countries. In a small open economy limited participation model, it shows the role of credit market frictions in the volatility of the nominal exchange rate. The empirical relevance of the model is statistically assessed by the method of simulated moments. In a two-country framework, local currency price rigidity and credit market frictions help explain the magnitude of real nominal exchange rate fluctuations. Beyond local currency price rigidity, firms' invoicing choices play a central role in the international segmentation of markets.

This thesis proposes an integrative approach to capital accumulation behavior and job search decisions in order to account for transitions in the labor market and more generally for contemporary fluctuations in unemployment. This integrative perspective draws its legitimacy from the close links between the traditional literature on job search models initiated by Phelps and a reflection on the market for capital, such as the questions of the sources of financing for research, the discount rate of its return and the adjustments to employment that give this factor a temporality similar to that of capital. We show in return that the recognition of these links is essential in both the positive and normative analysis of employment flows. From the point of view of firms, the introduction of endogenous adjustments of capital and interest rates, within the framework of stochastic matching models à la Mortensen and Pissarides, is able to account for the strong persistence observed in unemployment and job destruction rates. From this perspective, the introduction of employment protection can stabilize the economy and increase the welfare of risk-averse workers. From the point of view of risk averse workers, we show from micro-econometric estimates on the European Panel that their job search is strongly influenced by their wealth. We then reassess the welfare gains of unemployment benefits when we take into account the possibility for workers to self-insure by saving in a framework of incomplete markets. We show that saving is a poor substitute for benefits when we take into account variations in the interest rate and the duration of unemployment episodes over the business cycle.

The purpose of this thesis is to deepen the understanding of the fluctuations of the French economy over the period 1970-1998. In particular, it aims to take into account its openness to the outside world. Chapter 1 analyzes the dynamic properties of a small open economy model. The modeling of a small open economy implies the presence of a unitary eigenvalue. The aim is therefore to highlight, from a methodological point of view, the origin and the implications of this unit root. In the following four chapters, intertemporal general equilibrium models in a stochastic universe in a small open economy are developed. Each time, the model is calibrated on the French economy. We perform stochastic simulations as well as historical simulations in order to evaluate the ability of the proposed models to reproduce the stylized facts of the French economy. Chapter 2 of the thesis is devoted to the analysis of the impact of fiscal shocks on the fluctuations of a small open economy. We develop a model of perpetual youth, such an assumption allows us to eliminate the unit root inherent to this type of modeling of small open economy. Moreover, the Ricardian equivalence is no longer verified, as households have a shorter horizon, in expectation, than the state. Chapter 3 of the thesis explores the role played by external shocks in the fluctuations of the French economy. In chapter 4, I propose a model that reproduces the countercyclical character of the trade balance when it is subject to external and technological impulses, thanks to the consideration of a utility function that cannot be separated between consumption and leisure. The last chapter of the thesis proposes a monetary model of limited participation in a small open economy. We consider a model where shocks are transmitted through the credit channel.

The purpose of this thesis is to study the macroeconomic determinants of the exchange rate within the framework of the new international macroeconomics project. This trend integrates traditional Keynesian features, such as market imperfections, into intertemporal general equilibrium models whose microeconomic foundations are fully explicit. The models of the new international macroeconomics, which revive the teachings of Mundell and Fleming, have been confronted with the data using the methodology of real cycles. The first chapter reminds us that macroeconomic models are unable to explain the high volatility of real and nominal exchange rates or the interdependence observed between the main industrialized countries. The first part attempts to explain these two empirical puzzles by emphasizing the role of nominal impulses in exchange rate dynamics. In this respect, we show the importance of the presence of rigidities in the market for tradable (chapter two) and non-tradable goods (chapter three) as well as in the market for loanable funds (chapter four). On this last point, we show that overadjustment à la Dombusch [1976] is a quantitatively relevant phenomenon in explaining the volatility of the nominal exchange rate. The second part of this thesis is devoted to the study of the impact of the exchange rate regime on exchange rate dynamics and international fluctuations. Chapter five highlights the increased interdependence of the member countries of the European Monetary System in the post-accession period. Moreover, unlike real and nominal exchange rates, the variability of macroeconomic variables such as output, employment, consumption and investment is not sensitive to the nature of the exchange rate regime. In chapter six, we attempt to account for these two stylized facts.

The first part deals with the work that has led to the resurgence of the debate on the sources of economic fluctuations: we present and assess the scope of this work, which questions the influence of money on economic fluctuations. The second part provides new empirical evidence on the influence of monetary shocks in the economic activity of the main OECD countries, without however proposing a theoretical explanation of these effects. Finally, the third part focuses on the economic mechanisms that can account for the importance of monetary shocks in economic fluctuations.