Le Sauveur (1971)

AKA The Savior

Director: Michel Mardore
Cast: Horst Buchholz (Claude), Muriel Catalá (Nanette), Hélène Vallier (La mère de Nanette), Roger Lumont (Le père de Nanette), Henri Vilbert (Flouret), Danièle Ajoret (Nanette adulte), Michel Delahaye (Monnery), Jean-Pierre Sentier (Le mari de Nanette), Frédéric Norbert (Henri), Yves Hugues (Un fils Monnerv), Jacques Serres (Un fils Monnerv)

Here IMDB comment :

“A shocking war movie. Reminds of Verhoeven’s Flesh & blood

This strange, bold movie takes place in France during World War 2. A young and innocent girl (Muriel Catala) finds a wounded soldier (Horst Buchholz) and provides him food and help, hiding him in the cellar of her parents’ farm. Soon, a strange bond will unite those two, before the soldier reveals his true nature…

The sexual tension between the girl and the soldier may shock some people, but it’s just a piece of a bigger picture, as the movie turns out to show the manipulative characters looming to an atrocious ending, one of the most disturbing display of immorality ever put on screen. Not for everyone, but the movie is clearly worth a watch, if only for its rarity.”