According to L’Equipe, the teenagers are expected to be officially announced in the coming days as they prepare to begin their professional careers in Belgium.
Coulibaly, a highly rated centre-back and one of the standout talents in the PSG academy system, is regarded as a player with strong long-term potential.
Despite receiving a contract offer from the French champions, the teenager opted to reject it in search of clearer first-team opportunities abroad.
Ly, a French U17 international winger with two caps, also leaves the Parisian club after not being offered a professional deal. The Pontoise-born attacker impressed this season with 24 appearances, scoring five goals — including three in the UEFA Youth League — and adding three assists.
Both players were key members of PSG’s successful Gambardella Cup campaign, helping the club secure the trophy for the first time since 1991.