Saint-Antoine overlooks the approaches to the Fréjus Rail Tunnel and was part of an ensemble of forts, including Saint-Gobain, Ouvrage Sapey and Fort du Replaton that guarded the French end of the tunnel and the descent from the Mont Cenis pass.

A casemate is located nearby, but not connected to the underground gallery network.

[5] The fortifications of the Maurienne had suffered little damage during the war and by the end of 1944 were partly repaired and placed into service.

Immediately after the war, the Maurienne region was regarded as an area of medium priority for restoration and reuse by the military.

However, by 1960, with France's acquisition of nuclear weapons, the cost and effectiveness of the Maginot system was called into question.