For now it seems that Nagelsmann won't be welcomed with open arms in France by the people in general, by the media and perhaps also by his new team although the team shouldn't be a problem. They call him arrogant and they assume that he will be tested on a regular basis as soon as he gets under pressure. My opinion on that is that every coach knows when they go to PSG that it is all about pressure from morning till night as soon as you don't win a single game or even get problems in the Champions League. But when the public already has an opinion about him, it doesn't make things easier for him because everyone will be more skeptical from the beginning.
I tried to find information with what you said, but it seems that what you said is just your personal assumption. I don't get news and information regarding Nagelsmann will not be welcomed with open arms in France by the general public. but what is certain, according to The Sun Football report, PSG is now close to appointing Julian Nagelsmann as the new coach permanently. in fact, Fabrizio Romano also claims the same thing. PSG are working on Julian Nagelsmann's option as a real prime candidate for the job. other rumors, Thierry Hanry will be his assistant.
IMO, if Nagelsmann officially becomes PSG coach, I have the expectation that PSG will be much better in his hands. it's just that, Nagelsmann will need time to achieve something that is the target of PSG's management. except, Nagelsmann was given the privilege to bring in players who fit his criteria. unfortunately, so far there has been no news regarding the recruitment of Nagelsmann.
Speaking of Nagelsmann, I much prefer him over Galtier, Nagelsmann is a young coach who carries modern football. it doesn't matter what the French public thinks, but what is certain is that he has the capacity as a potential coach. that is why, Nagelsmann was targeted by several big clubs.