It is believed that Barcelona made contact with Barcelona to register their interest in the player over the summer, with club officials even flying to Paris.
However, Catalan daily 'Sport' is now reporting that the French club are accusing Barca of agreeing a deal with Rabiot come the end of the season, when his contract will be up.
If this is true, then PSG have made it clear that they will take the case to FIFA. Teams are not allowed to agree any deal with a player until they have under six months remaining on their contract.
To compound matters, Barcelona believe that PSG's reported interest in Ivan Rakitic is little more than petty retaliation, and the French side are simply making mountains out of molehills.
Relations have been strained between the two clubs since last summer, when PSG snatched Neymar away from Catalonia.