We use a combination of ex-ante and ex-post evaluation methods to evaluate a major welfare policy implemented in France in 1989. The policy granted an allowance (the Revenu Minimum d'Insertion, RMI, of up to 45% of the French full time minimum wage) to every individual above age 25 and below a threshold household income. The ex-post evaluation relies on the specificity of the Eastern part of France. In Alsace-Moselle, since 1908 and during German occupancy,...