When George Benson first appears as the French police chief, he uses his own Received Pronunciation, unmistakably British, very smooth speaking voice. About midway through the episode, however, his dialog begins to be dubbed by a gruff-voiced actor using a thick French accent.
In the scene where two characters arrive by car at a French airfield, a sign on a building next to the runway reads "The London School of Flying," revealing that the scene was shot there.