Sans Mobile Apparent (1971)

Synopsis
This hard-boiled French crime thriller begins with the bold murder of a well-heeled Frenchman. The detective assigned to the case is most puzzled for there seems to be no motive. Then a old man and an astrologer are killed in exactly the same way, leaving the detective to figure out how the three disparate victims are linked. All he has to go on is a mysterious diary given to him by the step daughter of the first victim. The diary belonged to him and contains a list of the man's lovers. One of those women was once the lover of the detective and he calls upon her. She, not knowing that he is on a case, hopes that he will renew their love. During their tryst, he learns that she knows all three of the victims, but before he can call her on it, she too is gunned down. Eventually it is the lover of the step-daughter who leads the detective to the mystery's surprising, shocking conclusion. Despite the film's noir-ish content, director Philippe Labro chose to film it in gay, sunny Nice, a technique that actually enhances the grimness of the suspenseful story. ~ Sandra Brennan, All Movie Guide