Aline Issermann’s “Shades of Doubt” (“L’Ombre du Doute”), a French film about a wrenching family crisis, is set forth with remarkable restraint. The subject is incest, but the story’s potential for tawdriness is never exploited. Instead, Ms. Issermann presents a discreet, methodical account of how 12-year-old Alexandrine comes to bring and then recant charges against her father, Jean.