"Based on a true story" ("D'après une histoire vraie" in the French original) is the latest film by Roman Polanski, and a late addition to this year's Cannes program. The film was adapted from the namesake novel by author Delphine de Vigan. In it, a writer (played by French actress Emmanuelle Seigner, Polanski's real-life wife) living in Paris publishes an autobiographical novel, and it does not go over well with her relatives who now