The aim of this project is to analyze the effect of marital breakdown on the tax behavior of taxpayers. What effect does marital breakdown have on the use of tax benefits? Does separation lead ex-couples to use more or less tax benefits? Or on the contrary, does separation have no effect on the greater or lesser use of these advantages? To do so, the project will use the difference-in-difference statsitcal method (to sompare the use of tax benefits the year before and the year after the one of the breakdown) and a matching method (to compare the evolution of tax benefits used by separated ex-couples compared to taxpayers who remained in couple throughout the period).