The French club must first present an International Transfer Certificate to FIFA confirming the move before Neymar is eligible to play, a usually routine piece of paperwork that in this case has caused the player's debut to be delayed.
And Goal understands that it is Barcelona who are holding up the process, as they await full payment of the mammoth fee to be completed before they yield the necessary documents to the Spanish FA (RFEF), who in turn are entrusted with sending them on to France.
Club sources insist there is no wrongdoing on their part, and that it is standard procedure for Barcelona in such cases to validate all transfer income before releasing a player's registration.
The RFEF also confirmed there were no issues with the Certificate.
"It is being handled following the normal process, it will be sent when it is ready," Goal heard from the governing body.
The mood in Paris, however, is far from calm.
PSG have until Thursday evening to register Neymar's International Transfer Certificate, or face losing the Brazilian for yet another Ligue 1 clash this weekend away to Guingamp.