This is according to Liverpool manager Jurgen Klopp.
"It’s pretty simple. Until now it was simply seen as impossible," Klopp told DAZN. "Then there is the list, with the release-clauses for Barcelona. Leo Messi, €300m.
"In a period of just a month that suddenly sounds possible too. That used to be an outrageous amount. They just set that amount randomly. I mean who would pay €300m. And now it simply happened."
The German added: "I don't even know if this is right. No coach would demand such a thing. That's been decided on other levels and now he is a PSG player, obviously. A simple solution would be a rule. Where we want to go and where this should stop.
"The biggest clubs can decide on that, where they would want to set a limit. €150m or €550m or whatever and then no one would complain anymore. This is a topic now since it happened for the first time."
PSG smashed the world transfer record with their capture of Neymar from Barcelona, more than doubling the €105m Manchester United paid for Paul Pogba to Juventus in August 2016.
Barca, who have five-time Ballon d'Or winner Messi on their books, and LaLiga have threatened to report PSG under the Financial Fair Play rules.