Hi everybody !
First of all, Qatari Royal family is only PSG's owner. For Monaco it's a russian businessman (Rybolovlev), For City it's the Abu Dhabi royal fund.
PSG won't lure Barça making them think they are willing to sell TS to finalize Marquinhos. Things don't work like that. Only thing PSG can do to keep TS right in his PSG shoes is to affirm he is a key player for the upcoming season(s), which they do. IF PSG used that kind of sneaky way you suggest, he could hamper clubs relationship.
Then, anothing thing is in French league we can only afford 4 extra-communautary players. At the moment, we are full: Lucas, Alex, Maxwell and TS.
So we can't buy Marquinhos if we don't sell at least one of them. The only one who is rumoured to leave is Alex. I also reported rumours we are interested in Hernanes who is EC too.
So unless you see Paris selling one of this guy, you don't have to worry about us buying Marquinhos. However, Leonardo interest is real. As i wrote you previously, he is seen like the new TS.
To speak about Barça, i'll be very disappointed if Rami ended to sign as the only CB. I have never understood all the hype around this guy. He is so bad.