No chance they join hands in that matter or another in the present or short future.Forgetting the politics of UAE and Qatar, I don’t know whether any tension between the owners or not, I wonder why City and PSG haven’t joined forces and worked against the devious workings of UEFA.
When you look at Football Leaks, you can see the pettiness at play. PSG owner got a deal with Infantino, then City owner got a better deal and wanted a promise PSG couldn't get the same treatment. At the end, Platini or Infantino promised but he ended up giving the same thing to PSG.
I think City would be happy to see PSG rot in hell. When you see the Asian Football Cup, it was a great deal when Qatar won in UAE territory and a pride issue.
And i'm sure that is one of the reason why PSG and Emirates ended their collaboration. Now that PSG is getting a bigger profile, it would have been an even better deal for Emirates if they had kept their relationship.
PSG will fight on his own and City will fight on his own. If one of them wins against the very core of FFP, it will benefit the other mechanically.
The big difference i see between PSG and City owners towards FFP is that City is a lot more aggressive and threatening in their message.