Le amanti (1973)

Complications abound in this French film, which tells the story of a filmmaker who is attempting to put his real life into a movie; his interactions with the people in the movie he is filming create reverberations in his "real" life, although the past remains unchanged. Among the complications is his growing regard for the woman who plays his cinematic wife. She may wind up replacing his actual wife in real life. One of the highlights of this film is the insight it gives into the actual mechanics of filmmaking.