Donnarumma to Real Madrid will interestingly complicated thanx to the kind of man Mino Raiola is.
First off, Perez doesn't like the guy one bit. Their relationship fell off deeply when Perez refused Mino's offer of signing Ibra when he left barca. Mino went on to rant how Perez denied his client the opportunity to spite barca. This is one of the main reasons Real Madrid refused to sign Pogba as well.
Secondly, the relationship Real Madrid has had with Jorge Mendes over the years. Mendes and Mino are the Messi and Cristiano of agents. Mendes and Perez have a sort of friendship that Mendes might use to convince Perez not to work with Mino.
Thirdly, we are a gentleman club. If Milan choose to complicate Donna's transfer, Real Madrid will pull back and watch. That's where PSG might come in and throw money around.
Lastly, Mino is a one greedy bastard. And given that Perez isn't fazed one bit by him, PSG might bait him the best way they know how, throw money at him.
Personally, I believe Real Madrid are the reason Donna refused to extend his contract, and not money(PSG) coz Milan were also offering a lucrative deal. Besides, it'll be ridiculous to leave a club like Milan for a club like PSG. Many sources also seem to support that as well. Only time will tell. It's finna be a loong and interesting summer for madridistas, buckle up.