340mm/45 Modèle 1912 Railroad Gun (France)

The 340mm/45 Modèle 1912 gun (13.4") was a heavy naval gun of the French Navy. While the calibres of the naval guns of the French Navy were usually very close to those of their British counterparts,[a] the calibre of 340 mm is specific to the French Navy.

The built-up gun was designed to be carried by the Normandie and Lyon classes in quadruple gun turrets, but no ship of these types was completed as a battleship. They were carried by the Bretagne-class battleships in twin turrets.