Tax incentives for work and research and development in France and their effects on the labor market.

Summary This thesis focuses on the monetary incentives to work and to R&D in the French socio-fiscal system, their evolution and their effects. We first simulate the incentives to work more (intensive margin) and to return to work (extensive margin) for the entire French population, taking into account all taxes on labor income and means-tested benefits. We show that incentives have increased at the bottom of the distribution since 1998 as a result of reforms in the 2000s, and that marginal tax rates have shifted from a U-shape according to income levels to a tilde shape. Then, we assess individuals' behavioral responses to these work incentives from social and tax reforms between 2006 and 2015. We show that the effects of marginal rates on labor income are relatively small overall but highly heterogeneous across individual characteristics. The responses would be stronger for income tax reforms than for reforms on social benefits. Finally, we study subsidies and tax incentives for R&D (research tax credit and lower contributions for young innovative firms). We show that R&D subsidy rates increased the most in the 2000s for small firms. For these firms, we evaluate the effect of the strong increase in R&D subsidies on employment devoted to R&D activities. This effect would have been positive and increasing between 2004 and 2010, but less than the increase in aid received between 2008 and 2010.