The North Star (1982)

Original title: L'Étoile du Nord

Edouard Binet, an aimless Frenchman, has been travelling in North Africa for many years, and is sailing to Belgium. En route, he meets Sylvie Baron. He introduces her to Nemrod Lobetoum, a rich Egyptian carrying valuable jewelry, and Sylvie and Nemrod become friends. Their friendship escalates to love, which makes Edouard jealous. Days later, Edouard arrives at a rooming house owned by Mme. Louise Baron, Sylvie's mother, wearing blood-stained clothes. It appears that Nemrod was killed on a train after he arrived in France, but Edouard denies any knowledge of what happened. Sylvie suspects that Edouard is responsible for Nemrod's death, but by now her mother has become Edouard's ally.