I am looking for a black-and-white movie that I saw before 1985. I think it was a foreign movie (probably from France). A couple visits a village/town where everybody suffers from memory loss. After a few minutes, the people just forget everything. The only exception is the duke of this town. The duke marries the young girls of the town and then he kills them. Since everybody forgets easily nobody is aware of the crimes (the victims are forgotten). I remember in one scene that the couple takes the villagers to the castle of the duke where they find the skeletons of the killed women. The villagers take the duke to the town center to execute him and then one asks the question: why have we gathered here? The Duke answers “We have gathered here because I am getting married” and he picks a girl from the crowd. The people forget his crimes and start celebrating the marriage. Unfortunately, I cannot remember the names of the actors, director, the end of the movie, etc. I saw it as a kid when I was just 10 years old.
Thank you in advance.

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