In the course of World War II the process of mechanisation was completed. The 3e and 5e RCA were equipped with M4 Sherman and M5 light tanks. The 5e RCA notably landed in Provence in August 1944, and was one of the first units to be fully operational for combat. It was engaged in several battles during the taking of Toulon, in the Rhone valley, through Burgundy, Alsace, and in the Black Forest. The regiment earned the Rhine and Danube badge.