Investigation reported to be targeting several contractor firms linked to club.
Ngoy, signed by Stoke from Brugge as a 15-year-old in 2013, is seen as one of the best young prospects in Europe.
Maxime Gonalons is close to leaving Lyon and joining Roma, the France international's agent has announced.
Arsenal have had an approach for Thomas Lemar rejected by Monaco, but remain hopeful of signing Lyon's Alexandre Lacazette, a source has told ESPN FC.
Fans shouldn't bemoan Paris Saint-Germain's quiet summer. There is finally a plan in place in Paris, and PSG's methodical approach should pay off.
Paris Saint-Germain have until Friday to secure Thiago Motta's future, according to the midfielder's agent.