Max, mon amour (1986)

Reserved and cool, Margaret is the French wife of Peter, a British diplomat posted to France with their son Nelson. She takes a lover, a chimpanzee she bought from a zoo and installed in a flat. Peter asks that she bring the chimp, Max, to live with them. He obsesses about Margaret and Max's relationship, hiring a prostitute so he can watch Max perform (Max declines) and peering through the keyhole as Margaret and Max sleep. He tries to kill Max, then finally accepts the ape's presence. When she is called away to her ill mother's bedside, Max stops eating. Worried, Peter takes Max and Nelson to the countryside so Max can be with Margaret; once there, Nature beckons. Is Max lost?