Bras de fer (1985)

Complex and more cerebral than a wartime action-thriller, this espionage drama focuses on the relationship of two former buddies who were fencing masters before the war and in love with the same woman. Now Delancourt (Bernard Giraudeau) is apparently living a good life managing a gym in a Paris hotel under Nazi control, where he meets his former friend Pierre (Christophe Malavoy), who is on a secret assignment to mislead the Nazis on the date of the Normandie invasion. Pierre, alias Augustin, cannot figure out if Delancourt is a real resistance fighter or if he is a double agent. Circumstances create a larger and larger gap between the former friends while the plot goes through several twists and turns before Pierre's doubts are resolved.

Unfortunately the movie Bras de fer is not yet available on HBO Max.