Uefa opened a “formal investigation” into Paris Saint-Germain on Friday after the French club broke the world transfer record to sign Neymar.
European football’s governing body said it would look at whether PSG had violated its Financial Fair Play rules.
“The investigation will focus on the compliance of the club with the break-even requirement, particularly in light of its recent transfer activity,” Uefa said in a statement.
PSG signed Brazilian striker Neymar for a world-record €222 million on August 3 and completed a loan move for Kylian Mbappe on Thursday in a deal that includes an option to buy the French teenager for €180 million.