PSG don't need him AT ALL, and he wouldn't do anything for them except waste money, PSG will walk the league every year for the rest of time... okay they'll have some screw ups, some injuries and miss a few titles, like 3, in the next 20 years. PSG could also potentially struggle in champs league due to FFP, and the likes of Ibra will get bored of the money soon enough and want to go to a real league... though price wise, I hope Ibra has a reasonable buy out clause then comes to the prem league, last one to win out of any that matter.
Assuming they stay in the champs league I don't think many truly top stars will go there after a couple years and their best players will want to go to a better league, and the sheer lack of top quality opposition week in week out will make it harder for a team like them to win the champs league.
If Jose went there, it would be for the money alone. But what club has Mourinho gone to, not wasted huge stacks of cash while upsetting half the players, selling club assets he shouldn't(Ibra, Robben) while wasting stacks of cash on often the wrong players and leaving a club with a huge wage bill, an attitude problem, a problem attacking, and a bunch of hangers on who for years to come will suck money out of the club.
Real are worse this year then when he joined, the season he won was only marginally better than Real the year before he took over, Barca got worse more than anything else, Chelsea/Inter were easy jobs at that time, champs league wins are genuinely tough accomplishments, but the more recent one was done playing the most extreme "anti-football" possible.
Utd would be mad to get him, they've still got significant debt to pay off and no owners pumping billions into the club while eventually writing off the debt. His spending/wages/management style won't work there at all. Back at Chelsea, he'll get the players working for him, at least for a while, and shore them up defensively, but long term I think he'll do the same again, load wages/transfer fee's on to the club, buy badly, waste money.... he'd win stuff at City but waste a lot of cash doing so. He's spent incredibly poorly at Real to date.