Although this is a French film, none of the three lead actors is French. Bronson and Perkins are American (although the latter seems to be playing an Englishman) and Jill Ireland is British, although she had been working and living in America for some years by then. The rest of the cast is European. In addition, the film was shot in an English version as well as a French one. The director was Hungarian.
Anthony Perkins and Charles Bronson got along very well during filming. Perkins said Bronson "was a doll" to work with.
One of the last films during Charles Bronson's "European Phase" before he became a big star in the US. Between that he was a character actor.