(1977) Alain Corneau - La menace

The administrator of a huge carrier Henri Savin lives with his lover Dominique Montlaur, who is the wealthy owner of the truck company. Henri decides to leave Dominique and the company to live with his mistress Julie Manet, who is two-month pregnant of him. However, Dominique does not accept the deal and stalks Julie. One night, Dominique offers money and fights Julie in a deserted fort, but she escapes from her driving her car. Dominique commits suicide jumping off a cliff and when Henri learns, he tells to Julie deny that they met each other in the fort since nobody would believe that Dominique killed herself. Julie is arrested for murder, and now Henri plants evidences to mislead the police and believe he is the real killer.