The Gros Ouvrage at Roquebrune is the second most southerly in the Maginot chain and is situated at a height of 321 metres. It had one entry block, two artillery blocks and one observation block. It overlooks and provided covering fire to Gros Ouvrage Cap Martin.
The fort would have been manned by about 300 men and the nearby barrack block survives. A few hundred rounds were fired from Block 2 in June 1940. Today the fort is used for storage by the local parks department.