Zinedine Zidane is a former French star and PSG is a France League team because of Zinedine Zidane's experience and strategy PSG offered Zidane to become their team manager but Zidane turned down the offer from PSG. PSG fans were somewhat angry with Zinedine Zidane for his behavior as he is not in charge of any team at the moment so why is he unwilling to take charge.
Zidane is a legendary player in France and contributed for them to win World Cup 1998 at home and Euro 2000. He went to another Word Cup final match with them in Germany 2006 but Zidane did a headbutt towards Materazzi and were sent off. France lost in that match in penalty shootouts against Italy.
He is still a famous guy in France and with his great success as Real Madrid coach, he aims at the France coach position. It is understandable as Zidane is very smart and ambitious. I don't understand if PSG fans show their angry against him but it maybe emotional reactions without logical thinking.
Zinedine Zidane may return to Real Madrid, which is why he did not agree to this offer from PSG. After Zinedine Zidane refused to coach PSG, Luis Enrique was appointed as PSG manager. Luis Enrique has been in charge of Barcelona for a long time. So I think he has no less experience than Zinedine Zidane.
I doubt he will return to Real Madrid a fourth time, first time as a player, two other times as their coach and perhaps he does not want to become their coach a third time.