Mélanie Thierry was 15 in Des gens si bien élevés when she played an uncredited character.
That was over 26 years ago in 1997.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 42, and has starred in 41 movies in total, 36 of those since Des gens si bien élevés was released.
In Des gens si bien élevés, I think Mélanie Thierry looks: