English publication 'The Guardian' reports that a £143m fee has been agreed between the two sides and that the player has agreed personal terms over a move but that the switch is being delayed due to FFP concerns.
The newspaper claims that football's ruling body, UEFA, is sceptical that the French giants can comply with FFP if they purchase Mbappe, having already signed Neymar for £198m earlier this summer.
EFA President Aleksandar Ceferin insists that FFP does work and says that any team that fials to comply with the regulations will be "severley" punished.
“We will try to help [the clubs understand the rules]. We will try to advise them on FFP. But if they don’t comply we will punish, and we will punish severely,” said Ceferin on Friday.
“I am not talking about [just] PSG. I am talking about every club in Europe. We are monitoring the situation, the transfer window is not closed yet. Trust me, we’re working on it.”
Although Monaco have been convinced to part with one of the hottest talents in world football right now, PSG must convince UEFA that they are capable of financing the deal before Thursday's deadline.