Trivia

Cinematographer Pierre Lhomme claimed that the last surviving, watchable print of the movie had turned completely pink with age. He later supervised the 2k resolution, digital restoration of the film at the Eclair Laboratories in Paris.

During the shooting of this film, Lino Ventura and director Jean-Pierre Melville did not speak to each other; they only communicated through assistants.

For the shot depicting German soldiers marching down the Champs Elysees, Jean-Pierre Melville thought that it would be impossible to get regular Frenchmen to provide the proper marching movements. He ended up casting dancers to correctly provide the march steps he wanted from the soldiers. This shot was originally the last in the film and prints were sent to theaters with it in that place. After the first showings, Melville decided the scene was better placed at the start of the film and it was physically spliced into the new position. This apparently resulted in several missing frames in the negative. These frames were restored from another source when the 2005 digital restoration was accomplished.

Late in the film, the protagonist, Gerbier (Lino Ventura), is hiding in a safe house in an isolated rural area, where he comes upon a set of books written by the head of his Resistance group, his friend Luc Jardie (Paul Meurisse). The books have highly esoteric titles such as "Essay on the Problem of the Foundations of Mathematics," "On Logic and the Theory of Science" and "Transfinite and Continuum." These titles, attributed to the fictional Jardie, were the actual titles of scholarly books published by Jean Cavaillès, a real-life philosopher, professor, and Resistance hero who was arrested by the Gestapo in February 1944 and shot to death in that April.

The Citroën car which the Resistance uses to pick up the traitor has large cylinders attached to the roof. This was a real conversion, one of a number made during the War because of the critical shortage of petrol (aka gasoline) for vehicles. This particular vehicle has been modified to run on natural gas, but the French also produced coal-burning and even wood-burning models.