Jess Franco's first film work was as the Spanish dubbing director for this Eddie Constantine film, the first in which the actor appeared as Lemmy Caution. The success of this film in France would translate into a series of Constantine-Caution films which includes Jean-Luc Godard's science fiction-noir ALPHAVILLE (1965).
Of course, Constantine would also appear in Franco's spy thrillers CARTES SUR TABLE and RESEDENCIA PARA ESPIAS (both 1966). The Peter Cheyney novel on which this was based was the first publication of the famous Serie Noire. Future Franco icon Howard Vernon also appears in this film which I would very much like to see. A final thought: the most recently completed Jess Franco film is also a kind of film noir featuring another hard boiled investigator, Al Pereira, a character also played by Constantine, Howard Vernon, Jess Franco and Antonio Mayans. If anyone has a copy of :LA MOME VERT DE GRIS please contact me. Thanks.