Fleury-Mérogis Prison is a prison in France, located in the town of Fleury-Mérogis, in the southern suburbs of Paris. With more than 4,100 prisoners, it is the largest prison in Europe. It is operated by the Ministry of Justice.

Fresnes Prison is the second largest prison in France, located in the town of Fresnes, Val-de-Marne, south of Paris. It comprises a large men's prison of about 1200 cells, a smaller one for women and a penitentiary hospital.