Paris Saint-Germain have agreed upon a €155 million ($185 million) deal with Monaco for Kylian Mbappe as well as contract terms. But UEFA may reject the move if PSG are unable to comply with financial fair play rules.

UEFA president Aleksander Ceferin said on Friday that it would punish clubs “severely” if they do not comply with the rules. “I am very serious,” he said on Friday. “We will try to help [the clubs understand the rules]. We will try to advise them on FFP. But if they don’t comply we will punish, and we will punish severely.”

He added: “I am not talking about [just] PSG. I am talking about every club in Europe. We are monitoring the situation, the transfer window is not closed yet. Trust me, we’re working on it.”

Mbappe was long connected to a transfer to Real Madrid, but PSG emerged strongly following their move for Neymar.