Tu es mon fils (2015)

The small seaside commune of Fouras is home to Claire Valent, a divorced mother of two now remarried to Paul, who has two kids of his own from a previous relationship. Claire shares custody of her teenage son, Raphäel, and daughter Lara with her ex, Marc, who lives on nearby Aix Island. Claire and Paul's families blend together well enough on the surface, but hidden tensions boil over when the lifeless body of a missing 15-year-old girl is found in a nearby swamp. A pair of missing sneakers leads Claire to suspect Raphäel might have had something to do with his classmate's killing. Unable to believe her own son could be capable of such a crime, Claire launches her own personal investigation into the murder, even enlisting her ex in the endeavor. But the deeper she digs, the more the evidence points to her son's guilt.