Born in Port-au-Prince, Haiti, to an Alsatian paternal family and an English mother, Philippe Kieffer obtained a diploma at the La Salle Extension University in Chicago.

Impressed by the techniques of the new British Commandos, formed in 1940, Kieffer requested authorisation to set up an elite French unit on the same model.

On 19 August 1942, men of the 1st Company of the 1er Bataillon de Fusiliers Marins Commandos were engaged during the Dieppe Raid ("Operation Jubilee").

In 1943, the French Commando had grown to two troops, and was regularly used for night raids on the shores of France and the Netherlands during the preparations for the invasion of Normandy.

Since Luxembourg did not have its own units, some Luxembourgish volunteers were incorporated in the "1er BFM Commando" and took part in the landings and battles of Normandy.

[1] On 6 June 1944, at 0731, the Bérets verts ("Green berets") landed in Ouistreham, Benouville, Amfreville and Bavent, designated as Sword Beach.