The Fort de l'Infernet is a fortification complex near Briançon in the French Alps. It was built as part of the Séré de Rivières system of fortifications in 1876-78 to defend France against invasion from Italy. It specifically overlooks the valley of the Durance behind and the Fort du Gondran, closer to Italy. Built at an altitude of , the fort was accessed by an aerial tramway, which connected to the older Fort du Randouillet at lower altitude. It was the last French fort to be built from cut stone masonry.