Maurice De Canonge's most estimable works are "Grisou" and "Les Trois Tambours" "Interdit De Sejour" should be restored to favor ,because it is a genuine film noir,in a way many others are not:the hero is a good guy,who works ;when he meets a femme fatale ,his descent into hell will never give him any respite .
An outcast everywhere ,particularly in the normal world in which he used to live in , he tries to find some help in the gangsters' world ,although he was betrayed by his girlfriend's brother , then to become an informer .Sometimes the viewer stops and wonders :"but an innocent guy such as him does not deserve such a raw deal!";this is tragic! The young lad is played by Claude Laydu , a perfect choice ;his peak was Bresson's pitiful priest in "Journal D'Un Curé De Campagne" ;and he was also cast as 'the most miserable schoolteacher in France" in Delannoy's "La Route Napoleon" ;at the time,nobody could play the victim as he used to do.
For all that,and against all odds,the movie (probably because of Albert Simonin's wit)is sometimes very funny ;the clueless lad thinks his love works in the international relations (!) which she does ,in a way ,for she is a whore in two Montmartre bars ,and there were American soldiers in France in the fifties! A young Michel Piccoli is also cast as a gangster ,and Daniel Cauchy Melville will use in "Bob Le Flambeur" plays the hero's evil genius.
Give this flick a chance!