Monaco have signed highly-rated France Under-20 goalkeeper Paul Nardi from Nancy on a five-year deal.
The 20-year-old, who has joined the Ligue 1 club for a fee of around £2.5m, will return to Nancy on loan for next season.
"Paul Nardi is one of the great hopes of French football. He enters our strategy to build with a long-term vision. We are delighted he has selected our project as we faced competition from other European clubs," vice president Vadim Vasilyev told Monaco's official website.
Nardi signed his first professional contract with Nancy last year after graduating from the club's youth academy.