The Fort de Saint-Cyr, located in the commune of Montigny-le-Bretonneux, (Yvelines), is one of the forts built at the end of the 19th century to defend Paris. 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 presently used as a film depository for the preservation of movies under the Cinémathèque française.