Cut off by German forces from the bulk of the French Army, the corps was evacuated to England and then shipped back to France in late May and early June 1940.

[1] The corps had various units assigned during the period of the Phony War, but by the time of the German invasion in May 1940, the corps commanded the 2nd and 3rd Light Mechanized Divisions (French: Division Légère Mécanique) (DLM), as well as some small reconnaissance and artillery units.

The Cavalry Corps in particular was noted for its solid performance during the Battles of Hannut and Gembloux during the fighting in Belgium.

At the same time that poorly trained French reservists were being defeated at Sedan, the Cavalry Corps met the German XVI (motorized) Corps of two Panzer divisions on equal terms at Hannut and in the Gembloux Gap.

From May 31 until June 10, 1940, the men of the corps were evacuated to England and then returned to France via the ports of Brest and Cherbourg.