Lyon president Jean-Michel Aulas has welcomed the world-record €222 million arrival of Neymar in Ligue 1 but voiced concern over the financial dominance of Paris Saint-Germain.
Aulas recently warned of the "dangerous bubble" created by PSG's wealth, but told France Football he was not against the move.
However, he said he had serious reservations about whether or not financial fair play (FFP) regulations worked.
"I am not an anti-PSG figure," Aulas said. "However, with the signing of Neymar, PSG's budget is at around €700m.
"As the club does not generate revenue to the height of such expenditure, this will unbalance an economy that was already struggling in the first place.
"There is also a positive, though. This might enable Ligue 1 to attract new partners and, particularly, negotiate new television rights."
Aulas denied he was jealous of PSG, saying: "On the contrary -- I applaud this. However, I do warn that a bubble has formed that could explode at any moment. This bubble cannot last.
"With all due respect to FPP, since Michel [Platini] left UEFA, they have lost one of its greatest defenders.
"If FFP is no longer a preventative measure in Europe, the state must be able to step in and take the decisions to check and verify where the funding for these sorts of things came from."
Neymar is still unable to make his PSG debut as the club wait for the French league to receive his international transfer certificate.
If the paperwork arrives in time he could yet play at Guingamp on Sunday, but it appears more likely that he will make his bow when Toulouse visit the Parc des Princes the following week.