It became a research center for the Commissariat à l'énergie atomique (CEA), France's Atomic Energy Commission.

As a result of this defeat, the Séré de Rivières system of fortifications was built from 1874–1881 to defend Paris, consisting of 18 forts, five redoubts and 34 batteries.

Construction started in 1876 on a roughly pentagonal fort with 48 artillery pieces and a garrison of 691 troops.

From 1955 the site was occupied by the CEA as a research center,[2] which considerably modified the fort and its environs.

[4] The large trapezoidal fort's main armament was a twin 155 mm Mougin turret.