Before the beggining of the war, Jacques Stosskopf was the deputy director of naval construction at the Lorient military shipyard. From September 1940, under the guise of collaboration with the Germans, he used his position to inform the Allied forces of each german submarine movement from the Keroman uboat base.

He was arrested by the Gestapo in 1944 and executed at Struthof camp in Alsace. He was posthumously awarded the Legion of Honour after the end of the war and his name was given to the Keroman submarine base in July 1946.