One of the best films playing at Cannes isn’t in the official selection, but in Directors’ Fortnight, a separate program that runs concurrently with the main event. The glorious, gorgeous “The Florida Project,” directed by Sean Baker, had its premiere on Tuesday and rapidly became one of the most talked-about titles. Set in Florida, on the outskirts of Disney World, it centers on young children living with their parents in seedy motels off the highway, the kind where sex-by-the hour transactions are as much a part of scene as palm trees and misplaced tourists.

Speaking the day after his premiere in a restaurant overlooking the beach, Mr. Baker (who shot his last movie, “Tangerine,” on an iPhone), said he was thrilled to be at Cannes but more so for his performers, a few of whom were milling about. “It obviously feels great,” he said, adding, “I’m so happy that my little actresses are here. I can’t even imagine what it must be like through the eyes of a 6-year old.”

Later, as he talked about the casting process, which included convincing adults that he wasn’t a creep off the street, one of his young stars, Brooklynn Prince, wandered over. “Are you jet-lagged?” he asked. “No,” Brooklynn said, flashing a gaptoothed smile — she was just getting started.