This study aims to contribute to the economic literature on the long-term evolution of social and income inequalities and its main causes, through the French case since 1970. The objective is to measure the deformation of distributions (and not only inequality indicators) and estimate the contribution of technological, demographic and political changes. The project will make use of the Enquête Revenus Fiscaux surveyx. These data, newly made available, are the result of matching between survey data on the socio-demographic profile of households (family composition, profession, activity status) and tax and social data on income (income from activity, pensions, taxes, social benefits).