In Their Sleep (2010)

IMDB
Genre : Horror, Thriller
TRAILER
Director : Caroline du Potet, Éric du Potet
Stars : Anne Parillaud, Arthur Dupont, Thierry Frémont, Jean-Hugues Anglade
Plot : One year after her teenage son's death, Sarah's life is in pieces. One night, her car accidentally hits Arthur, a young man the same age as her boy, who is running from a mysterious assailant who is hunting him down.