He could sign a 5 year contract, rack up some titles and be out at 23/24 not even in his prime yet. You'd need very solid advisors and entourage not to get pressured into signing new deals after new deals if you aspire to bigger european clubs.
This is true. Must remember though that he is French and there are obvious parallels between City and PSG though they are a bigger club historically in there own country and I know its not something people liek to hear, but there is a lifestyle option too being in your home country and it is Paris.
It is pretty much the equivalent of a yougn English talent signing for City at the moment and City being in London.
He is only 18 after all, like you say he can be there five years, win a lot of silverware domestically for sure, get a lot of money, stay in his own country and he would only be 22/23 and if fully established look for that career defining move, has time on his side. I mean, face it, he would be the same age then as Mason Mount is now.
Really it is probably the sensible option for him at this point in his career....would be disappointed though, as he is the perfect signing for me foru s this season, not at £100m though