With the fall of France in May 1940, the German Army captured a lot of French Army tanks and vehicles. One such Beutepanzer trophy tank was the very large Char B1 bis heavy tank. Many of them had been abandoned by their crews after running out of ammunition or fuel. The design contract was given to Rheinmetall-Borsig, which was based in Dusseldorf. They created blueprints for a mount placed on top of the tank chassis that could take the 10.5 cm leFH 18/3 artillery howitzer. The gun crew would be protected from small arms fire by an open top armored casement. Designer M Bergman
