The SOMUA S35 was a French cavalry tank of the Second World War. Built from 1936 until 1940 to equip the armoured divisions of the Cavalry, it was for its time a relatively agile medium-weight tank, superior in armour and armament to its French and foreign competitors, such as the contemporary versions of the German Panzer III medium tank. It was constructed from well-sloped, mainly cast, armour sections, that however made it expensive to produce and time-consuming to maintain.

French development into tanks began during World War I as an effort to overcome the stalemate of trench warfare, and largely at the initiative of the manufacturers. The Schneider CA1 was the first tank produced by France, and 400 units were built. The French also experimented with various tank designs, such as the Frot-Laffly landship, Boirault machine and Souain experiment. Another 400 Saint-Chamond tanks were manufactured from April 1917 to July 1918 but they were underpowered and were of limited utility because the caterpillar tracks were too short for the tank's length and weight. The most significant French tank development during the war was the Renault FT light tank, which set the general layout for future tank designs and was used or redesigned by various military forces, including those of the United States.