The line was substantially modified during the 1930s as Line 10 took over the western section. The current route serves the southwestern part of the city, the Grands Boulevards and Bois de Vincennes, ending in the southeastern inner suburbs through the communes of Charenton-le-Pont, Maisons-Alfort and Créteil, which the line reached in 1974 at Créteil – Préfecture station, after several extensions. The underground line was the first to connect the prefecture of one of the new departments of Île-de-France. The only Paris underground line to cross the Seine and its principal tributary, the Marne, above ground via a bridge between Charenton – Écoles and École Vétérinaire de Maisons-Alfort, it also crosses the Seine underground between Concorde and Invalides.