Monaco have paid Lyon £17.5m for 16-year-old striker Willem Geubbels.
Geubbels made two appearances in the French top flight last season and was the first player born in the 21st century to play in Ligue 1.
“The arrival of Willem Geubbels proves our ambition to develop the best talent in European football at our club,” director Vadim Vasilyev told the club’s official website.