RAGOT Lionel

The share of the foreign‐born population in member countries of the OECD is increasing, and this article summarizes economics research on the effects of immigration in those nations. Four broad topics are addressed: labour market issues, fiscal questions, the political economy of immigration, and productivity and international trade. Extreme concerns about deleterious labour market and fiscal impacts following from new immigrants are not found to be warranted. However, it is also clear that government policies and practices regarding the selection and integration of new migrants affect labour market, fiscal, social and cultural outcomes. Policies that are well informed, well crafted and well executed beneficially improve population welfare.

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This thesis proposes an evaluation of the pension system in Morocco and its ongoing reform process, using a dynamic microsimulation model. It is structured around two distinct and complementary parts that allow us to build the scenario of extending pension coverage for non-salaried workers. In the first part, we begin by studying the nature of the demographic changes facing the pension system, the way in which past reforms have tried to respond to them and the unresolved issues. Then, using data from the Haut-Commissariat au Plan, we carry out an empirical study that measures informal employment, identifies its characteristics and determinants, and examines the reasons for its existence, i.e., whether it is suffered or chosen. The second part of this thesis consists, in the first instance, in describing all the work carried out in the construction of the dynamic microsimulation model. We then develop a detailed explanation of the steps and techniques adopted and written in R language, using programming tools developed for the rewriting of the Destinie model of INSEE. Subsequently, we propose an evaluation of the last parametric reform of the Moroccan Pension Fund (2016), comparing it to the projected evolutions using the programmed model. Finally, we use the same model to simulate reform options to create pension coverage for informal workers.

The WIOD (World Input-Output Database) project led by the European Commission since 2009 has been able to take advantage of the development of statistical sources on international trade in recent years to harmonize the input-output tables of many countries at a global level. This database renews interest in input-output analyses inspired by the work of Leontief, adapted to the framework of a world economy. It is now possible to follow the propagation of a shock at the global level. The thesis is in line with this revival by trying to evaluate the inter-sectoral and international chain of events of a shock on energy prices, and its impact on unit production costs. The originality of this paper is that it seeks to go beyond the usual limits of input-output analysis by allowing an endogenous deformation of technical coefficients over time.The thesis seeks to take advantage of the econometric literature on flexible functional forms, applied to the analysis of production, to overcome this main limitation. The interest of the flexible cost functional form of the Generalized Leontief type is more particularly discussed insofar as it covers as a special case the usual input-output model. The thesis proposes to use a nested sectoral modeling and gives an important place to the theory of indices to achieve this in the most coherent way possible. The model thus developed is finally estimated in order to carry out simulation work on the effects of a carbon tax in European countries on the cost competitiveness of the different sectors in these countries. We study the effects of a carbon tax at 20€/tCO2 or 80€/tCO2 first at the European level. The analysis of cost competitiveness reveals that Poland and Spain would be the main losers of this tax while the other European countries manage to preserve their competitiveness vis-à-vis the rest of the world. A similar study on a tax applied unilaterally on France or Germany shows that these countries will be only slightly affected.

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In a context of internationalization of higher education and research, we address two issues related to the recent dynamics of national university systems. First, using a microeconomic supply-side approach, we show that the degree of public intervention and the non-rigid capacity of institutions explain the divergence in tuition fees between regulated and deregulated university systems. Then, using a demand-side macroeconomic approach, we try to understand the factors of inelasticity of demand through gravity models including non-price determinants of international student mobility.

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In this paper, we introduce a unified Ramsey model where pollution has an impact on preferences and affects both consumption demand and labor supply. Pollution comes from production activities and is viewed as a stock variable with a strong inertia. A government is introduced and levies a proportional tax on production to finance depollution expenditure. We find two interesting results when pollution raises the consumption demand (compensation effect). First, in the long run, a higher green-tax rate increases the pollution level at the steady state (green paradox) when pollution raises the labor supply (disenchantment effect). Second, in the short run, local indeterminacy can arise through a Hopf bifurcation when pollution lowers the labor supply (leisure effect) even if pollution has a strong inertia.

This thesis is devoted to the study of the implications of uncertainty on environmental policy. The debate around uncertainty has intensified in the context of climate change and sustainability. Many recent studies examining environmental policy have shown how uncertainty can alter economic behavior. This thesis contributes to this growing literature on uncertainty and environmental policy. To this end, Chapter 2 aims to present a new explanation for poverty traps through the presence of disaster probability. I present a new trade-off between adaptation and mitigation policies other than the usual dynamic trade-off highlighted in many studies. Many recent reports from international institutions have begun to highlight the importance of building a market economy through R&D innovations that manage adaptation and mitigation investments. Chapter 3 builds a Schumpeterian growth model in which investors manage adaptation and mitigation investments. Chapter 4 focuses on individual preferences and sustainability. This chapter aims to show that the sustainability criterion may not be consistent with optimal decisions in an economic model with a possibility of catastrophe when there are limit cycles (Hopf bifucation). Therefore, the criterion should be revised by policy makers to include the possibility of limit cycles.

The issue of immigration in host economies is nowadays at the center of political, economic and social concerns. Immigration is perceived today as a problem rather than an opportunity for host societies in general and France in particular. The results of the Transatlantic Trends survey between 2008 and 2013 show that in France, public opinion on immigration has deteriorated significantly. To the question do you perceive immigration as a problem rather than an opportunity? 50% of French respondents answered in the affirmative in 2013. This percentage was only 39% in 2008. In parallel to this situation, demographic projections show an aging population and immigration could be a solution to this problem. The objective of this thesis is to analyze, in this context of demographic aging, the economic effects of immigration by focusing on its impact on public finances and household demand in France. It thus contributes to the literature on the costs and benefits of immigration in host countries. It also analyzes the economic consequences of a policy decision on immigration, testing the effects of changes in migration policies on public finances and the effects of income increases on the consumption of native and immigrant households. The thesis is structured around two main parts: the first part focuses on the budgetary impact of immigration, with an accounting assessment in the first chapter and a dynamic assessment using a general equilibrium model in the second chapter. The second part of the thesis focuses on the consumption of immigrants in France. Here again, two chapters are distinguished: the first measures the contribution of immigrants to final demand and the second analyzes the consumption behavior of native and immigrant households.

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This thesis studies the optimal choice of pension system in Palestine. The Palestinian economy is characterized by a very low level of social protection and a high poverty rate. The first chapter presents an analysis of the demographic, social and economic environment in Palestine. The second chapter provides a review of the literature on social protection systems. The third chapter analyzes the rate of access to the social protection system as a function of different socio-economic s characteristics. The fourth chapter presents an econometric analysis of the decision to participate in the pension system. The fifth chapter, using the PROST model (World Bank), proposes a prospective analysis of the pension system in Palestine. The prospective study determines the appropriate contribution rate according to several unemployment scenarios and its impact on the balance of the pension system taking into account the specific situation of women in Palestine.

Demographic aging in France is a major concern and is the subject of several studies from an economic point of view. Most studies highlight the negative effects of aging on the French economy, particularly on social welfare accounts and the labor market. Recently, a new literature on aging has emerged. This literature seeks to identify and show how aging can be an opportunity for the economy. This thesis is part of this literature. It seeks to answer the following question: Can aging be an opportunity for the French economy? To answer this question, the thesis explores the savings and consumption tracks, with an emphasis on the consumption part. The thesis is articulated in five chapters. Chapter 1 describes the causes of demographic aging in France and reviews studies on the effect of this phenomenon on the French economy. Chapter 2 analyzes the evolution of income, consumption and savings over the life cycle and across generations in order to understand the evolution of aggregate consumption and savings in an aging society and with generational turnover. These results also make it possible to compare the standard of living of different age groups and generations. Chapter 3 focuses on the evolution of the consumption structure according to age, generations and following a change in household income. Chapter 4 starts from the observation of the change in consumption structure over time, the difference in consumption structure between working-age households and senior citizens to estimate equivalence scales from 1979 to 2010, for senior citizens and working-age households. These scales make it possible to compare the standard of living of seniors and working-age households, taking into account economies of scale within the different households. Finally, Chapter 5 uses a general equilibrium model to quantify the effect of aging on the consumption, production and employment structure.

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Immigration is often seen as an instrument of adaptation for ageing countries. In this paper, we evaluate, using a dynamic general equilibrium model, the contribution of migration policy in reducing the tax burden associated with the ageing population in France. Four alternative scenarios, compared with a baseline scenario based on official projections, are simulated with the aim of quantifying the effects of immigration on French social protection finances. We show that the age and, to a lesser extent, the skill structure of immigrants are the key features that mainly determine the effects on social protection finances. Overall, these effects are all the more positive in the short to medium term if the migration policy is selective (in favor of more skilled workers). In the long term, the beneficial effects of a selective policy may disappear. But whatever the degree of selectivity of the migration policy, the financial gains from higher consequent migration flows are relatively moderate compared with the demographic changes implied by ageing.

The objective of this thesis is to define the role of health care expenditures in the French health care system and, in particular, to identify the extent to which health care represents a cost or an investment. It is based on a study of the interdependencies between health care and sick leave for more than 100,000 employees monitored between 2009 and 2012. The results demonstrate the dual preventive and curative component of any care.Our first work consists in identifying the additional cost of care due to ill health, based on a model regressing the cost of care on the fact of having been absent in 2012: there is then a significant cost of this care assimilated to consumption.Based on a Poisson model with inflation of zeros, we then reflect on the determinants of sick leave, and in particular on the role of the sector of activity in a portfolio of private sector employees. It appears that while the difference in sick leave reflects working conditions, the disparity in duration is more akin to employment conditions and social climate.We also look at the preventive role of health care, since it significantly reduces the future number of days of sick leave, using a fish model on panel data that takes into account the problem of initial condition.Our final classification of health care utilization and sick leave behavior shows health capital as a continuum in which investments are made.

The question of whether migration can serve as a channel for regional adjustment to asymmetric shocks is crucial in an economic and monetary union. It is of particular interest within the Eurozone where countries do not have flexible exchange rates as an adjustment mechanism. By moving from countries with high unemployment to countries with better employment prospects, intra-European migrants should help countries to adjust to asymmetric shocks and lead to a more efficient allocation of resources within the free migration regime. This policy brief exploits the 2008 economic crisis to investigate how labor market disparities between EU15 countries affected intra-European migration. Our main contributions are threefold. First, over the period 2000-2013, we find that intra-European migration indeed responds to regional differences in employment conditions: a rise in unemployment differences between two EU15 countries fosters migration to the country with the better employment conditions. Second, we find that the 2008 economic crisis led to a strong reallocation of individuals within the EU15 between the southern countries (Greece, Italy, Portugal and Spain) which were the most affected by the crisis and the least affected countries, such as Denmark and the UK. Third, our results indicate that responsiveness to regional employment disparities is far greater among non-EU15 immigrants, compared to European-born people. This finding suggests that the mobility of Europeans within the EU15 could be greater, a hypothesis that is consistent with the higher mobility observed in the United States. Improving cross-country portability of social rights within the EU could thus be a relevant reform to foster intra-EU mobility.

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The objective of this thesis is to verify whether the baby-boomers are at the origin of a break in intergenerational equity in France. It is based on an application of the National Transfer Accounts method, which provides an age-specific measure of consumption, individual resources, savings and public and private transfers between 1979 and 2011. Projections are also made to the year 2060 using the MELETE model for public transfers received and disposable income. The results, which are established with regard to the main criteria of intergenerational justice, do not show a clear and generalized break in intergenerational equity, even if French society is characterized by certain inequities concerning the distribution of income from assets and the distribution of retirement pensions between generations. Moreover, this thesis provides results that are useful for understanding family solidarity in France. Over the last thirty years, the increase in the economic weight of donations and inheritances has coincided with a decrease in the weight of aid within households and a stability in the weight of aid between households. The result is that private transfers between households are less and less adapted to the needs of the beneficiaries, which is corroborated by a micro-econometric panel analysis that shows that events experienced by donors can trigger the payment of donations, unlike aid between households, which depends exclusively on events experienced by the recipients.

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The French population is aging and will continue to do so in the future. The negative consequences of this demographic change on the economy are well known. However, the extent of these consequences will depend, among other things, on the evolution of labor productivity. In order to analyze the future evolution of labor productivity in France, this thesis focused on the role of health care expenditures in the economy. Indeed, on the one hand, health expenditures, by improving the health of the population, increase labor productivity. On the other hand, they promote the aging of the population by increasing life expectancy. Thus, this thesis aims to verify whether the productivity gains generated by health expenditures are sufficient to cancel out the negative effects of population aging. We theoretically demonstrate that private health expenditures generate a positive externality improving labor efficiency and consequently labor productivity (Chapter I). However, our empirical results underline that this positive effect is not significant when we consider health expenditures that remain at the expense of patients (Chapter II). The productivity gains allowed by the future improvement of French health are then measured using a generational accounting model. The productivity gains appear to be significant but insufficient to offset the negative effects of demographic ageing (Chapter III). This observation is confirmed by the results provided by our general equilibrium model (Chapter IV).

Immigration is often seen as an instrument of adaptation for ageing countries. In this paper, we evaluate, using a dynamic general equilibrium model, the contribution of migration policy in reducing the tax burden associated with the ageing population in France. Four alternative scenarios, compared with a baseline scenario based on official projections, are simulated with the aim of quantifying the effects of immigration on French social protection finances. We show that the age and, to a lesser extent, the skill structure of immigrants are the key features that mainly determine the effects on social protection finances. Overall, these effects are all the more positive in the short to medium term if the migration policy is selective (in favour of more skilled workers). In the long term, the beneficial effects of a selective policy may disappear. But whatever the degree of selectivity of the migration policy, the financial gains from higher consequent migration flows are relatively moderate compared with the demographic changes implied by ageing.

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The purpose of this thesis is to ask how to improve the management of wetlands and associated goods/services. By integrating multidisciplinary knowledge into management models, we study economics as a tool for the service of Man and Nature. We propose to improve the management of wetlands by combining an economic approach with a biological approach in order to be able to account for the complexity of these environments in economic models. To do this, we base this thesis on the study of the ecosystem functions provided by wetlands, which are the habitat, production and regulation functions. The habitat function is addressed through the issue of the accessibility of wetlands in the Gironde Estuary to migratory fish species. The production function, closely linked to the habitat function, is studied through a theoretical model of the sharing of a wetland between fish production and agricultural production. Finally, we deal with the regulation function by integrating this function into a program to encourage the reduction of agricultural pollutants and the restoration of wetlands.

The question of people's preferences for forest recreation services is becoming increasingly important in urban planning considerations and strategies. The literature based on the hedonic price method for the evaluation of forest recreational services generally questions the accessibility of the nearest forest and considers the provision of recreational services as homogeneous. However, our hypothesis is that in urban and peri-urban environments, households may have preferences for the diversity of forest spaces in their residential environment. Evaluators need to understand the complementarity of forest spaces on a territory and question the overall forest environment and its variety in terms of recreational services. The objective of our first study is to estimate and compare the impact of proximity to forest recreational services on real estate prices when considering the nearest forest on the one hand and the overall forest environment, which includes the spatial heterogeneity of recreational services, on the other. We highlight the importance of considering the forest environment in economic evaluations in order to best estimate the recreational value of forests. In a second work, using auction function estimation, we investigate how the socio-economic profile of households influences their preferences in terms of recreational services of the forest environment. The results allow us to deepen our knowledge of preferences around "nature in the city" issues. They reveal heterogeneous relationships to the forest environment and its recreational qualities, which depend on the profile of the households. Finally, in a third section, we start from the observation that in the case of multi-site amenities, individuals can choose to visit different sites and at different frequencies. Using a theoretical model calibrated on real data, we reconcile Alonso's spatial approach with the accessibility of a multi-site amenity in Rosen's hedonic approach. We conclude that when there is a preference for a multi-site amenity with heterogeneous levels of quality, a misspecification of distance in hedonic models significantly impacts the evaluation of the amenity.

Recent empirical contributions have observed a significant negative impact of pollution on labor supply. These impacts have been largely ignored in the theoretical literature, which has focused on the effects of pollution on consumption demand. In this paper we study the short- and long-run effects of pollution in a Ramsey model where pollution and labor supply are non-separable arguments in households' preferences. We determine sufficient conditions for the existence and uniqueness of a long-term equilibrium and we show how large (negative) effects of pollution on labor supply may promote macroeconomic volatility (deterministic cycles near the steady state) through a flip bifurcation. © IAET.

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Questions relating to the integration of immigrants and their descendants are not new in the economic literature. However, they have mostly been dealt with from the point of view of the economic efficiency of immigration or discrimination. Cultural assimilation, on the other hand, is regularly at the heart of public debate, particularly through the notions of national and cultural identity. The theory of identity appeared in economics about ten years ago and has made it possible to improve the understanding of individuals' decisions when they define themselves by their membership in one or more groups to which norms of behavior are attached. Using this theory, we look at the extent to which cultural identity, considered as the expression of the cultural assimilation of immigrants, allows us to improve our understanding of socioeconomic inequalities. After recalling the importance of the family context and the level of education in the professional success of immigrants and descendants of immigrants, we analyze the formation of cultural identity. If ethnic identity decreases with time spent in the host country, it also depends on the way it is measured. We then show a negative impact of ethnic identity on access to employment and political participation but a neutral impact on wage level. Finally, using a controlled laboratory experiment, we test more generally the significant influence of group identity on individual decisions.

This thesis focuses on improving the robustness of climate change mitigation policy evaluation techniques, as well as the robustness of implemented instruments. By exploring hundreds of scenarios that capture uncertainty about future technological, sociological and demographic developments, as well as about the availability of fossil resources and the implementation of mitigation policies, it reveals the determinants of future emissions and mitigation costs. This methodology allows for the filtering of decision-relevant information and focuses the debate on issues and policies central to the success of greenhouse gas emission reduction policies. The thesis also proposes to focus the debate on instruments that are robust to political constraints because they have few negative short-term impacts. Policies that redirect investment towards low-carbon capital - such as energy efficiency standards or financial instruments - bring us closer to long-term emissions targets without affecting the owners of the polluting capital already installed.

This thesis investigates the determinants of location choices of internationally mobile students and international students. A global analysis focuses on the determinants of student migration to OECD countries. Using estimation methods found in the literature on international trade (Poisson regressions), it appears that, in addition to the traditional determinants of labor migration, the quality of education in the destination countries is a strong determinant of student migration. Moreover, a network effect, by qualification, has been highlighted. An analysis of the determinants applied to the French case confirms the results of the previous study and highlights a network effect by age as well as a strong sensitivity to the costs borne by students during their studies (real estate prices, etc.). This thesis also evaluates the macroeconomic impacts of student migration on the French economy using a computable general equilibrium model with overlapping generations. Receiving and training international students represents a cost, but this cost can be offset by an increase in the economy's human capital stock, which translates into a higher GDP growth rate. Nevertheless, the magnitude of the gains depends on the size of the student flows as well as on the share of students trained in France who will enter the French labor market once their studies are completed (retention rate). Student migration also has an impact on the financing of the French pension system by changing the ratio of inactive to active workers.

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The thesis is devoted to the study of dynamic games in the climate domain. To fight against the accumulation of greenhouse gases in the atmosphere, the implementation of a carbon tax is a possible solution. However, it is assumed here that this carbon tax has motivations for fossil energy consuming countries that are not limited to the internalization of environmental damage: it is a strategic behavior to try to capture part of the producers' rent. This leads to the possibility of a carbon tax with a Pigouvian but also strategic purpose. Non-cooperative dynamic games between supposedly cartelized producer countries and supposedly cartelized consumer countries can then be envisaged in this context. A literature on non-cooperative differential games has been developed over the last twenty years around the idea of a carbon tax with a strategic aim. In the introduction, we recall the economic framework of these games, their analytical framework (differential games) and the related theoretical literature. We present three games that form the body of the thesis. Each of the following three chapters is devoted to an original differential game. The first game is a non-cooperative game between a block of consumers and a block of producers with a pollution cap as the main environmental constraint. The existence of this ceiling changes the classical conclusions of this type of game. In the second game, there is also a non-cooperative game between a block of consumers (rich countries) and a block of producers, but there is also a second block of consumers (poor and emerging countries), which does not play in the game but implements the carbon tax resulting at each moment of the game in return for a transfer from the first block of consumers. It appears that under certain conditions the second block has an interest in this "carbon tax versus transfer" scheme. In the third game, there are also two consumption zones, but they are now playing a non-cooperative game with each other, the producers being passive. There is a carbon tax per block and not a global one and yet the game shows under certain conditions a better situation for the consumption blocks than a passive situation towards the producers. The overall conclusion of these three games is that, under certain conditions, the consumer countries may have an interest in strategic and not just Pigouvian behavior with respect to carbon taxes.

On the one hand, the adoption of polluting technologies can enhance the factor productivity. on the other hand, pollution lowers the stock of human capital by weakening physical and mental performances, and short-ening the life expectancy at the end. To capture the impact of pollution on economic growth, we compute the optimal policy in an endogenous growth model `a la Lucas (1988) and we study the effects of pollution in the short and the long run.

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This thesis seeks to determine the economic and political factors that influence voting in French municipal elections. It seeks to test the hypotheses underlying economic voting in French municipal elections, using an original and detailed database covering the period 1983-2008. We show that the incumbent party is punished if the macroeconomic situation is bad. Conversely, the incumbent party is a victim of the national political climate, especially in periods of cohabitation. Moreover, local environmental variables also influence the incumbent's score in the 2001 election. This thesis also concludes that electoral behavior is complex, with varying degrees of sociotropism revealed: for fiscal variables, the local level is taken into account by voters, while the national level is of interest for macroeconomic variables (unemployment). Finally, the two-round voting system is not insignificant in determining the municipal vote. Thus, the structure of local budgets is a determining factor in the first round. More specifically, high per capita spending on salaries and equipment increases the probability that the incumbent party will be re-elected in the first round, while operating expenditures (excluding salaries) reduce it. Conversely, certain political factors (e.g., the number of candidates running) only come into play in the second round.

In this thesis, we study the effect of market imperfections on macroeconomic stability in the standard Ramsey and OLG models. To carry out this objective, we use the method of local dynamics analysis introduced by Grandmont, Pintus and De Vilder (1998). The imperfections we use are externalities in consumption, imperfections in the credit market, the presence of a progressive tax on wage income and the existence of transaction costs associated with capital accumulation.

The conference of experts held on July 2 and 3, 2009 in Paris on the theme of environmental taxation is a concrete example of the rise of a general awareness, which goes beyond the field of analysis of economists and scientists, on the need to develop public policies at the national, regional and international levels likely to influence behavior and trigger a process of change towards a model of production and consumption that is environmentally friendly. This awareness of the problem of the unsustainability of our current growth model, which has now been extended to civil society actors, non-governmental organizations, and quite simply to every citizen, was preceded for several decades by both theoretical and empirical research on the various economic and regulatory instruments of public policy likely to make our way of life viable in the long term.

The purpose of this thesis is to evaluate the trajectory, liquidation and longevity risks associated with funding. After a first chapter reviewing the literature, Chapter 2, which is essentially historical, is devoted to calculating the replacement rates that funding could have provided from 1900 to 2003. We show that the risk reduction provided by diversification is small and very costly (in terms of replacement rates). Chapter 3 is devoted to the evaluation of the path risk - measured by the probability that the replacement rate falls below a certain threshold - by the parametric bootstrap method. We estimate the probability of reaching these threshold replacement rates, as well as the savings rate required to reach them with a given probability. The minimum replacement rate imposed by the Fillon law is out of reach with the current funding and contribution rates. The advantages of the multi-pillar system are quite limited. The main one is the reduction of extreme risks. We also show that the probability of failing to reach the pay-as-you-go replacement rate with funding increases with the duration of contributions. In Chapter 4, we compare different strategies for programmed withdrawals to a life annuity. A risk/return approach is adopted where the return corresponds to the expected annuities and possible bequests and where the risk is measured by the probability of not obtaining a certain pension level. We show that this risk can be very high, regardless of the drawdown strategy. No alternative distribution strategy can compensate for the risks associated with the capital accumulation phase.

This thesis focuses on understanding the economic effects of immigration by comparing the cases of France and the United States. Immigration changes economic conditions. of the host country through two main channels: the labor market and public finances. Two types of approaches are proposed to study the issue: generational accounting and computable general equilibrium. This thesis first shows that the current immigration policy appears to be very neutral on fiscal balances in France. The level. The level of education of migrants is the determining variable of their impact on the economy considered. Thus, the implementation of a more selective policy on the level of education of future flows generates long-term gains. If the educational level of migrants is at the heart of their fiscal impact, then extending the analysis to the whole population leads to a reduction in fiscal imbalances due to educational progress. Second, using a computable general equilibrium model confirms these results for both countries. Contrary to the recent literature, we show a non-negligible net gain from immigration but moderate redistributive effects. The model also shows that post-war immigration to the United States has had only a small impact on macroeconomic variables, but that it increases the welfare of all the native-born cohorts considered.

In a closed economy with perfect competition, Barro [1990] demonstrates the existence of an optimal size of public intervention: when the government finances productive infrastructure, the growth-maximizing tax rate is equal to the elasticity of output relative to public infrastructure. It is therefore determined by purely technological considerations. In the first part, we lift the assumption of perfect competition. Under imperfect competition in the market for capital goods, and in the absence of discrimination, we show that the optimal size of public spending can be increasing with the price elasticity of government demand (representing here an indicator of the efficiency of government management), and even exceeds that obtained by Barro under perfect competition. In the second part, we return to the closed economy hypothesis. When economies are interdependent, we show that even if the size of public infrastructure is strongly constrained by the mobility of capital, governments retain some room for manoeuvre in the choice of this size. A process of economic integration, such as that of the European Union, does not necessarily lead to downward tax harmonization.

Two remarkable results emerge from the literature on exogenous growth with pollution. It is necessary to impose ad hoc conditions to ensure the sustainability of growth (homogeneous pollution function of zero degree, green exogenous technological progress). Moreover, consumers have no active role in the search for a sustainable growth path. We then construct an applied general equilibrium model in which households have the option to consume both polluting and green goods. The trade-off between these two goods results from a preference for green goods that depends on the quality of the environment. Different variants of environmental fiscal policies are presented, depending on the intermediate objective set by the state (modification of the consumption basket or reduction of pollutant emissions associated with production). When economic growth is endogenous, sustainability can only be achieved by ad hoc assumptions similar to those imposed in exogenous growth models. We propose a model, in continuous time, in which the taste for diversity of consumers is at the origin of a qualitative endogenous growth process and their preference for green goods conditions the quality of the environment. The possibility for the state to influence the quality of the environment through consumer awareness campaigns then appears. The model, written in discrete time, does not systematically converge towards a stationary state, but its evolution can become cyclical or even chaotic for certain values of the ecological sensitivity of households. Their optimal behavior then consists in intermittently reducing their demand for polluting products, thus providing the environment with respite periods allowing it to assimilate some of the accumulated pollutants.