An Only Son (1969)

Original title: Un fils unique

A teenage boy and his friend look up an artist who painted a picture of the boy's mother years before. The eccentric artist eventually tolerates the intrusions of the two teens and gives the boy some historical background on how the two met and became involved. When the boy tells his mother he has met the artist, the mother returns to him and rekindles the passionate affair the two shared years before. The boy is caught in the middle between his mother's infidelity and his own resentment and rebellion towards his conservative, often humorless father.