With the exception of the subtle violin tune heard during the final shots and closing credits, and the creepy piano music in the bar, the film has no musical score.
The scene where Marc and Bartel talk over dinner was modeled after the conversation scene between Marion Crane and Norman Bates in Hitchcock's Psyco (1960).
According to director Fabrice du Welz the surreal bar scene in this film is a homage to one of his favorite films André Delvaux's Una sera... un treno (1968).
Laurent Lucas' audition for the role of Marc lasted 45 minutes as he performed the scene where Marc puts on his show makeup and extended out the scene as though it were a real event.
Writer/director Welz said he purposely wanted to create the characters in the film against type, by fleshing-out and sympathizing more with the character of the villain rather than his victim.