The MP-56 was a compact submachine gun designed by Louis Bonnet de Camillis and manufactured by Erma Werke.
After Erma briefly manufactured the French MGD submachine gun, which resulted in little financial gain, the company tasked their engineers with producing a short, compact weapon with a rate of fire of about 550 rounds per minute. They took up a design from Frenchman Louis Bonnet de Camillis, which was dubbed the MP-56. It was designed in the early 1950's and finished in 1956. Only ten were ever made. Fenner Achenbach, the sponsor and financial controller for the weapon, decided to hand over the production rights to Mauser instead. The resulting weapon was the Mauser MP-57.
The MP-56 was made in two forms: the first had a collapsible stock and grip safety. It used MP-40 magazines. The second model had a folding foregrip wrapped around the barrel and no shoulder stock. This model was intended for police units. With both models, the bolt was wrapped around the barrel. It fired in full-automatic mode only.