Sweet Evil (2010)

Céline, a fifteen-year-old girl, fled from her guardians. She took up residence in the outbuilding of a bourgeois house, unbeknownst to its owners, judge Van Eyck and his wife. Discovered one evening, she manages to gain acceptance, and day after day, tries to seduce her new guests. Until a series of revelations leads them to doubt that his presence is due to chance.