Just got back from France, here's the short answer - you most definitely need the pass. But you don't need it immediately upon landing, you can wait until you're settled in the city. Every restaurant will ask for it, Christmas markets will ask for it, places selling food may or may not ask for it, the train will ask for it. In fact, SNCF at least at the Gare de l'Est has a two-step policy - you not only need the PS, you have to show it to someone beforehand and they slap a blue wristband on you.
Now having said that, I took a daytrip to Strasbourg. As I said they were very strict in the Paris station, but not there. In Strasbourg not only was there no ticket check before boarding the train, there was no PS check. That surprised since, since it was a TGV train hence a longhaul headed only to Paris.
Here's how I got my pass. When we were checking into our hotel the desk clerk was taking copies of our passport and CDC cards and said would you like me to get your PS for you? Well hell yeah, sure. She said she knew a nearby pharmacy and she would give them copies of those documents and get the pass made for us. Sure enough a few hours later she said your passes are here; they were paper printouts with the all-important QR code. She offered to somehow get them onto our phones but I was happier with the piece of paper, which everyone accepted. This was another good example of why you need euros in pocket once you hit the ground, since she needed cash to take over to the pharmacy.
I was looking around baggage claim at CDG to see how one might get the PS at the airport and I just didn't see it. So not sure you should count on doing it that way, there didn't seem to be any easy non-security way to get into an area of the airport with commerce.