Nasir Al-Kilafi that own Paris Saint German is from Qatar, so having world class footballer like Kylian Mbappe is something huge for them because the upcoming World Cup would be played in Qatar. He already have almost all the world class footballers but only Christiano Ronaldo is not there. Lionel Messi, Kylian Mbappe and Neymar junior. Only these 3 men's endorsement can bring huge amount of money to the club they play for and that's why Al-Kilafi can't just let them go. Most especially Mbappe because he is still young and he would surely bring something huge for them in the future.
Even has Neymar Dasilva has dropped point, I am very sure that they won't want to leave him to go this summer, until the World Cup finish because they just want all starts to be in their club. Even if it's possible for them to sign Christiano Ronaldo, they would go for him because as it seems, the salary to give their players isn't their problem, they just want all stars in France ligue 1 just like the way it's in English premier league but I doubt that one is possible because stars would never finish in England, and the English premier league is the most all over the world.
If Kylier Mbappe has signed for Real Madrid, he would surely be the phase of laliga as Laliga has no player that's bringing them endorsement anymore after Lionel Messi has left the club. Only Kareem Benzema is the start there but the endorsement he'll give to Laliga can't ever be like the one that Mbappe will give them due to his age and it's this season he shine most in all seasons, if he has been shining always like Ronaldo Mbappe and Messi, the endorsement he'll bring might be a huge one.