The Somua SM was originally developed as part of a competition between AMX and SOMUA to produce a heavily armoured tank that shared similar components and parts, due to the French army forcing both companies to work under identical specifications. The order to build a prototype was given in 1946, but the vehicle was only delivered in October 1951, weighing 56 tonnes but still lacking an engine. In contrast, the AMX-50, the SOMUA SM's direct competitor, had already been tested, and a variant of the AMX-50 with a 120 mm cannon was already being designed. Ultimately, the SOMUA SM was not tested until 1953, by which point the AMX-50 Surbaissé had already been delivered for testing, and the AMX-50 (TOA100) had been deemed insufficient due to its armament. These delays would doom the project, leading to eventual cancellation of the project and scrapping of the only constructed prototype.

Introduced in Update "Raining Fire" as a premium pack in the Gaijin store, the Somua SM will be a familiar tank to French players; it possesses the excellent 100 mm SA47 L/58 autoloaded cannon that is equipped on both the Lorraine 40t and AMX-50 (TOA100), while featuring similar mobility. Unlike the tanks previously mentioned, however, the Somua SM possesses decent armour, capable of bouncing almost all APCBC and even some APDS rounds aimed to its hull and upper turret front. The armour on the Souma SM, combined with the slightly larger ready rack for the gun compared to the Lorraine and AMX-50, allows the player to use the tank more aggressively.