La Redoute des Trois Communes is a French fort which was built in 1898, in the Authion mountain chain under the command of Général Séré de Rivières.
In the 1870s, relations between France and Italy were conflictual. When the Comté de Nice became part of France (24th March 1860), it made Authion even more important as it had become a border chain, the keystone of defending the Maritime Alps. Huge fortification works began to make any possibility of the Italians breaking through impossible. Access to the chain was facilitated by several strategic roads being opened, leading to La Redoute des Trois Communes (1898) and to the forts of La Forca (1883-1890) and Mille Fourches (1883-1890).