In France, the AC-556 is known as the Mousqueton A.M.D. where it was used by several governmental agencies within the French Interior Ministry: the Police Aux Frontières ("P.A.F."—Border Police), the Police Nationale Compagnies Républicaines de Sécurité (or "C.R.S."—Riot Control Brigade) and the Groupe d'Intervention de la Gendarmerie Nationale ("GIGN") special operations unit. The A.M.D. come in two versions, the first has the standard Ruger aperture rear sight. On the other, the aperture rear sight has been completely removed and replaced with a tangent rear sight located on top of the barrel just forward of the receiver.