According to OBSESSION: THE FILMS OF JESS FRANCO* this 1952 French thriller, featuring Eddie Constantine (CARTES SUR TABLE, RESEDENCIA PARA ESPIAS) and Howard Vernon, may have been Jess Franco's first professional level job in the Spanish film industry. He was responsible for dubbing the film into Spanish. I haven't seen this film but Vernon reportedly was typecast as a villain, a role he would play in numerous Jess Franco films starting with GRITOS EN LA NOCHE (1961), almost ten years later.
The film was adapted from a Peter Cheyney novel by Bernard Borderie, who also directed.
*P. 33-The Classical Years: 1952-1965