Social security financing and balance between generations.

Summary This thesis is devoted to the financing of social security. It is a theoretical analysis of the problems related to the financing of social security within the framework of a general equilibrium approach with overlapping generations. The thesis consists of three parts, each of which is divided into two chapters. The first part is intended to introduce this research. The theme of the second part is the financing of social insurance. The last part deals with the financing of social savings, similar to the second part. The starting point of the research is an evaluation of the policy of financing social security in the short and long term. The first chapter thus considers the examination of short-term social security planning. The country of application is France. The concern of the second chapter is to establish a framework of analysis adapted to the medium-long term: economies with imbricated generations. The second part presents two contributions on the financing of social insurance according to an actuarial or fiscal logic. The first logic is justified when the process generating social inequalities is individually perceived as random. Conversely, the fiscal logic arises when the inequality is perceived as deterministic. In the name of a certain <>, redistribution can then be implemented. The third part consists of two contributions on the financing of social savings. Redistribution can restore a certain intergenerational justice and propose a portfolio diversification for households. Secondly, if the actuarial method provides a better return than savings invested in the social security system, then it should be chosen. The question then is to what extent it is possible to propose a tax reform plan that is equal to the improvement for all generations.