I really don't think they are lying.
To host any big international sporting events, there is always corruption going on.
I don't even need to believe on the sources or journalists mentionned. You won't get to host anything if you don't give some "sweets". And the funny thing is Qatar didn't even win the bid. It went to UK.
Still, that has nothing to do with PSG. This is the problem with Nasser being the figurehead of lot of businesses for Qatar. People will try to associate that with PSG.
It is the same as saying that Hoeness criminal activities that put him behind bars are related with Bayern Munich.
And again, Nasser didn't get elected by UEFA. He got elected by football presidents and CEO to represent them in UEFA. That means that if he bribed someone to get his position, he bribed the whole football presidents. I don't get how people still don't get that.