Les Montagnes russes (2012)

A mature man and father takes advantage of the temporary absence of his wife and son, who have gone on vacation for the week, to try his hand at a romantic adventure. He stayed in Paris for work, while she, young, pretty, smiling, and lonely, was in the bar that evening, just like him. He is not exactly her age, but let's say he has the attractive physique of a man who is graying elegantly. They quickly hit it off, and he invites her to come back to his place for one last drink...