Brazilian Neymar sealed a world-record £200m switch to PSG from Barca in August 2017.
In his first season, he won three trophies including the Ligue 1 title.
PSG have won all of their league matches so far this season and look like they’ll retain the title unchallenged.
The lack of competition in the French top-flight has sparked talk that Neymar could be set to return to Spain.
Real Madrid have been linked with his signature while a move back to the Camp Nou remains a strong possibility.
And former Brazil and Barcelona midfielder Edmilson believes the star should never have left in the first place.
“Neymar’s career is a very personal theme,” he told Goal.
“He decided to go to PSG and leave Barcelona and in my opinion, that was a mistake.
“A World Cup was coming and, if he wanted to be number one, he would achieve it faster at Barca than being at PSG with all due respect to them.”
The 42-year-old then took aim at the lack of competitiveness in Ligue 1.
“He’s having a hard time because in Ligue 1 PSG are two or three steps ahead of other teams,” he added.
“It’s not that the opponents are bad, it’s that PSG has an international squad.
“For an international squad to compete with clubs it’s a complicated matter.
“I hope he can stay focused and be enthusiastic because this is important for a player, regardless of his talent.
“If he’s not happy, if he’s not living football as his profession… he can have the most beautiful hair in the world but it won’t deliver what it wants.”
The 26-year-old came off injured in Brazil’s friendly against Cameroon leaving PSG sweating over his fitness ahead of their must-win Champions League clash with Liverpool next week.