Listed as a Historical Monument in 1925 and bought by the city three years later, the citadel of Sisteron was requisitioned in 1940 by the military and then the civil authorities to serve as a house arrest center. Temporary buildings were erected there to house first political internees joined and then replaced, from the summer of 1942, by convicts and common law prisoners. The camp was successively guarded by French prison guards in 1940 and then by German soldiers from 1944. The appalling living conditions and the supply issues forced transfers to other detention centers such as Fort-Barraux.