The Casque Adrian modèle 1926 was used by the French and Belgian armed forces during the World War II.
The French and Belgian forces used the Adrian helmet in the Battle of France. After the French capitulation, Vichy France, the French Resistance and some units of the Free French Forces adopted it until 1951 in the French army and the 70s for the French police.
The design of the helmet was based on the M1915 Adrian helmet, standard helmet of the French Army during WWI. Some improvements were made in the 1926 variant, chiefly stamping the helmet shell out of a single piece of steel (the 1915 version used a separate bowl and brim) and replacing the long ventilation slot of the original with a series of smaller ventilation holes for additional durability. Helmets used during the Battle of France were painted mustard-brown, which had been adopted as the standard uniform color of the French Army in 1935.
After the war, the 1926 Adrian was replaced by the Casque Modèle 51 based on the American M1 Helmet.