The Ligue 1 club's €222m signing of Barcelona's Neymar has left them with little to play with in terms of transfer funds, despite the club's interest in Mbappe.
Many expected the Parisian club to be unchallenged at the top of the French League as they began the campaign after winning the Ligue 1 four consecutive times in the previous seasons.
Neymar will make his full debut on Sunday, after being declared unavailable to appear in PSG's Ligue 1 opening win at the Parc des Princes against Amiens due to registration issues, despite being with the team before their opening league game.
It's been almost a week since Neymar landed in Paris, and the world's most expensive player still can't play for his new club in the French league.
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Paris St Germain may not be done with their big spending just yet.
"To beat, or even draw, against PSG you have to be on a really high level prior to matchday". The fact that Neymar, Mbappe and Cavani could be PSG's front three next season is outrageous.
"We received the CIT and Neymar can play on Sunday", a spokesperson for the LFP said in a statement to BBC Sport.
It is not only about Neymar's transfer fee, the market is inflated and teams are not afraid to pay over the odds for a player of their choice to strengthen their teams.
The 18-year-old started in their opening 3-2 victory over Toulouse last weekend, as captain Radamel Falcao found the net.
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