The first star to arrive at the 77th Cannes Film Festival walked on four legs. Messi, the dog from the film “Anatomy of a Fall,” made a grand entrance on the Cannes red carpet on Tuesday before the opening ceremony. Photographers in tuxedos eagerly called out “Messi! Messi!” as the border collie paraded past them and ascended the stairs to the Palais des Festivals. There, Messi sat down and raised his front paws, mimicking a movie star waving to the crowd.