 François enrolled in the Schutzstaffel (SS), in August 1941 and for a time he was the leader of the Flemish SS.Seeing action on the Eastern Front, he rose to the rank of Obersturmführer (First Lieutenant) in the 27th SS Volunteer Division Langemarck.After the war he was sentenced to death, but the sentence was commuted to life imprisonment, and he was released in 1952.