Porte de Montreuil is a station on line 9 of the Paris Métro. The station has four tracks, two of which are sidings. Like that of Porte de Charenton, the train hall boasts an unusually wide vault, at 22.5 m across. The station is named after the Porte de Montreuil, a gate in the nineteenth century Thiers wall of Paris, which led to the town of Montreuil. Flea markets are held on the glacis of the fortifications.