Both players have been linked with mega-money summer moves to Spanish giants Real Madrid, with that speculation only intensifying after the departure of Cristiano Ronaldo left 'Los Blancos' one world star short.
However, Fernandez, who is now working as sporting director for PSG's academy, insists that both players want to remain at the Parc des Princes this summer.
Speaking to 'Radio MARCA', Fernandez said: "Neymar has decided to stay at Paris Saint-Germain. He wants to succeed, after not achieving it at the World Cup. I think that he wants to win titles with PSG.
"Mbappe? He stays too. He has said it, one hundred percent. He wants to win the Champions [League] with PSG. Financial fair play? It does not worry me. The important thing is that both Neymar and Mbappe want to stay at PSG."
Such has been the level of speculation that Madrid have been forced to issue statements denying that they have bid for either player.