Paris St Germain has again flexed its considerable financial muscle, signing French teen Kylian Mbappe on a deal reportedly worth up to €180 million (NZ$299m) - making him the world's second highest paid footballer after fellow August signing Neymar.
Paris Saint-Germain have signed French young forward Kylian Mbappe from AS Monaco on a season-long loan deal.
Following the closure of the transfer window in France on Thursday and confirmation of Mbappe's switch to Parc des Princes, it took less than 24 hours for UEFA to announce it would be launching an investigation into the French club.
The UEFA statement said its financial control board had opened "a formal investigation into Paris Saint-Germain as part of its ongoing monitoring of clubs under Financial Fair Play (FFP) regulations".
Clubs must not post losses in excess of €30m over a three-year period under FFP and PSG are widely thought to have structured the Mbappe deal with that restriction in mind.
Despite a massive outlay on players, PSG has failed to get past the quarterfinals of the Champions League in the past four seasons, and only once made the semifinals back in 1995.
"I was seduced by the project of the club, which is one of the most ambitious in Europe", Mbappe said.
PSG have already smashed the world transfer record this summer, having acquired Neymar from Barcelona for €222m.
The club president, Nasser Al-Khelaifi, added: "It was essential for French football that we keep and help develop such a great talent in our championship".
The Ligue 1 giants have secured themselves France football's golden boy for the next few years at least and should he eventually move on, to Real Madrid perhaps, they probably stand to make a healthy profit.
Once PSG signed Neymar, the chances of Monaco holding onto Mbappe went down.
Carlo Ancelotti didn't rate the midfielder too highly in front of the others he had at his disposal and he struggled for game time all season.
The events of recent weeks means there can be no doubt over PSG's capacity to do so now, although they risk further setbacks if they are unable to prove they will comply with FFP rules.
"Paris Saint-Germain acknowledges the decision of the UEFA Financial Fair Play panel to immediately ensure that the Paris club's accounts are in line with the Fair Play criteria, as of 30 June 2018 for the 2017/2018 season", PSG's statement read.