After the first world war the fort was used as an army weather station and arms depot.

Classed in 1992 as a monument historique, it is now used as a film depository for the preservation of movies under the Cinémathèque française.

As a result of this defeat, the Séré de Rivières system of fortifications was planned and constructed to defend Paris.

The fort itself was located in what was then the commune of Bois d'Arcy, now in the town limits of Montigny-le-Bretonneux.

[1] Construction on the Fort de Saint-Cyr began in May 1875 and was completed in 1879, with troops installed the same year.