I think it’s a French movie. The only scene I’ve seen is where a boy climbs a ladder to look at a girl through a window. She is possibly wearing a cheerleader or majorette hat, and dancing. Other boys try to climb the ladder to see. Then the girl closes the curtains. Thanks!
I don’t know the movie yet, but literally saw that clip on one of the “adult” sites (like xvideos etc) searching for “flashing” about 2 days ago, so it must be in there.