That's the predicament Delon finds himself facing in the final film directed by Julien Duvivier. He's probably best known for Pepe le Moko, a big early hit for Jean Gabin that was remade in the U.S. as Algiers, a big early hit for Charles Boyer. Duvivier fled to the U.S. during WW2 and most prominently made the portmanteau films Tales of Manhattan and Flesh and Fantasy. In the last year of his life the 70 year old director made a vivid and sometimes campy psychological thriller that has strong film noir elements and touches of expressionism. It gets a bit clunky toward the end when we finally have to have the plot explained, but what carries us through is Alain Delon's performance and the sexual tension between him and Berger, who together may form part of a triangle or quadrilateral.
Duh, how do you say femme fatale in French? Senta Berger enjoys the attentions of the actually-German Peter Mosbacher as Kim.
Expressionist and other touches from director Duvivier and cinematographer Henri Decae
The plot, once revealed, seems a little over-elaborate, and some details probably would have been better off left mysterious. It can't help but be a clunker of a moment when Delon discovers that the voices in the night are coming from a good-sized tape recorder stuck between his mattresses. But the sexual tension among the four main characters transcends the sometimes creaky plot mechanics, and the payoff when Delon defies doctor's orders and does it with Berger is undiluted by the implausibility of the core conspiracy. Duvivier exits on a minor but graceful note, ably assisted by Delon and Berger. It's no great ultimate statement, and I doubt that Duvivier had anything like that in him. It's just a last modest confirmation (on top of the few other films I've seen from him) of his skill at making entertaining films.
Here's a jazzy French trailer with plenty of male chauvanist mayhem, uploaded to YouTube by Annie7676:
A cinematic pun? Diaboliquement Votre was Delon's first film after Le Samourai, but unlike in Jean-Pierre Melville's crime masterpiece the actor sort of dresses like a samurai here.