In the 1950s DEFA was already testing the AMX 50 heavy tank. Even though it proved to be quite powerful DEFA decided that they also wanted a heavy SPG. That is when they started working on the CA AMX 50 (Canon d'assaut A.M.X. de 50t) which was supposed to provide long range fire support to the AMX 50 heavy tank with its powerful 120mm Cannon. The project ended after it was deemed to be too heavy and too slow. Only 1 prototype was made