The ouvrage is located about one kilometer north of Monte Grosso.

It was placed to control the Col de Brouis and the D 2204 road between the Breil and Sospel.

Col de Brouis was built by a contractor named Borie starting in November 1931 and completed in October 1934, at a cost of 11.4 million francs.

Two observation posts reported to Col de Brouis, including Cime du Bosc.

[5] Col de Brouis saw little action in 1940, but was the scene of significant combat between retreating German forces and the Allies in April 1945.