This film and also "13 Rue Madeleine" are loosely based on the real exploits of one of the few US Marines to serve in combat in the European Theater during WW2. A former Foreign Legionnaire, Colonel Peter Julien Ortiz, USMC Ret, was an officer with the OSS and led Operations Union I & II in southern France - training, supplying and leading the Resistance against the Germans in 1944-45. His adventures earned him two Navy Crosses and were so incredible one would hardly believe them in a movie.