Thiers wall
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 (the sloping bank in front of a wall) of the fortifications.