Jacques Doillon's La Fille de 15 ans (1989)

Juliette (Judith Godrèche) is fifteen and in love with the slightly younger Thomas (Melvil Poupaud), although they aren't quite yet ready to move into a sexual relationship. Willy (Jacques Doillon) is Thomas's divorced father who decides to take his son and girlfriend on holiday with him to Ibiza, in a villa by the sea. It's when Thomas decides to swim out to a rock and explore it, spending most of the day in this pursuit, that Willy begins to move in on Juliette, although in a subtle way.
Slowly he begins to fall in love with her, much to her annoyance, and she tires of him so often simply looking at her. Speaking about the matter with Thomas, she decides to bring the thing to a head by leading the father on, enticing him, only to dump him at the last moment. Although 'dump' is far too harsh a word to use in this film which is a subtle exploration of what Doillon is good at: the research into youth and its intricacies.