UEFA has confirmed that it has opened a Financial Fair Play investigation into Paris Saint-Germain.
The French club paid a world-record transfer fee of £198m to Barcelona for Brazil international Neymar last month, who is believed to be on wages of £515,000 per week.
In addition, PSG also recruited Monaco forward Kylian Mbappe on loan on transfer deadline day, with an obligation to pay a £166m fee for the player next summer.
In a statement, the European governing body said: "The Investigatory Chamber of the UEFA Club Financial Control Body has opened a formal investigation into Paris Saint-Germain as part of its ongoing monitoring of clubs under Financial Fair Play (FFP) regulations.
"The investigation will focus on the compliance of the club with the break-even requirement, particularly in light of its recent transfer activity.
"In the coming months, the Investigatory Chamber of the UEFA Club Financial Control Body will regularly meet in order to carefully evaluate all documentation pertaining to this case.
"UEFA considers Financial Fair Play to be a crucial governance mechanism which aims to ensure the financial sustainability of European Club Football.
"UEFA will make no further comments on this matter while the investigation is ongoing."
European football's governing body introduced the FFP 'break-even' rules in 2013, requiring clubs to balance their spending with their revenues.
Giuseppe Labellarte
