European movie: two families of friends; week-end camping; girl abuse and accidental murder

Hi.

A thousand years ago I’ve watched an European movie where two families of friends went camping together one week-end…
A male adult ends up trying to abuse one young girl of the opposite family and accidentally killing her.
…And that’s all I can recall.

Does it ring any bell? What could possibly be it’s title?…

Thanks in advance for any clue you can provide!