Le crépuscule des loups (1988)

In Paris occupied by the Nazis, a young boy plays his violin alone in a park. He is spotted by a SS high rank officer, who soon learns he is an war orphan. The music-lover officer is going to take care of the boy's musical education, while his subordinates are torturing French prisoners in the basement of his big house. But is this young boy really whom he pretends to be.