Income Inequality across French Departments over the Last 100 Years

Abstract

In France, married couples or couples in civil partnerships must declare their resources jointly and are allocated two tax units. This tax system, referred to as the marital quotient, represents a financial package of around 10 billion euros. Using the Ines microsimulation model, we simulate three reforms of this system: an individualisation of taxation, a reduction of marital quotient to 1.5 tax units while allowing married couples/couples in civil partnerships to opt for individual taxation and, finally, the capping of the marital quotient at the same level as the family quotient. Individualisation results in the highest tax gain (around 7 billion), compared with 3.8 billion when the marital quotient is reduced to 1.5 tax units and 3 billion with the marital quotient cap. With these reforms, 46%, 45% and 7% of couples lose out, respectively. The median losses correspond to 1.5%, 1.3% and 2.6% of the disposable income of the households concerned, respectively. Finally, 60%, 64% and 83% of the losses are in the last three standard of living deciles, respectively.