Essays on macroeconomic policies in heterogeneous agent models[Essais sur les politiques macroéconomiques dans des modèles à agents hétérogènes]

It is now recognized that the heterogeneity of economic agents plays a crucial role in understanding the fluctuations of an economy. The different chapters of my thesis serve the same question: How does heterogeneity changes the way economic policies should be conducted? Today, heterogeneous-agent macroeconomics is developing in several directions, each shedding different light on the problems we face as economists. My thesis is at the confluence of the different facets of this field. The first chapter of my thesis, participates in the heterogeneous agent macroeconomics that derives analytical solutions in reduced-heterogeneity models. I study how governments should increase or decrease taxes on firms over the business cycle. I show that taking into account firms heterogeneity greatly changes tax policy recommendations. The second chapter of my thesis is part of quantitative heterogeneous agent macroeconomics. We study whether monetary policy should use its ability to redistribute wealth among heterogenous households to achieve its objectives. The third chapter of my thesis participates in field that uses micro data to understand macroeconomics and to design public policies. I estimate firms' propensities to invest to better understand how economic policies can vary firms' investment by varying their income.