I have been in France for nearly three weeks. Let me tell you my experience regarding the pass.
Hotels--half of my hotels have asked for the pass upon check in. A couple have said so they don't have to check at breakfast.
Restaurants--all but one has asked for the pass to eat indoors. (It was just a slip up with me as I saw them checking others.)
Trains--i have taken numerous trains that have required the pass. Announcements are constantly made about needing the pass. On none of those trains was I asked for the pass. But then, I wasn't asked for my ticket either.
On my next to last train, a group of SNCF police came on board and went through the train. But all they did was check to make sure people had masks on.
As Kim stated, you do not need the pass for local and regional trains.
Museums--all asked for the pass.
I have the Pass Sanitaire so it wasn't a problem. I was only in Paris to change trains. I was in Bayeux, Colmar, Mulhouse, Beaune, Lyon, Carcassonne and Toulouse. I heard NO English spoken on the street from Colmar to Lyon. They have not seen many Americans or Canadians since they reopened in the summer. I asked about the CDC card and most looked puzzled. They had no idea what I was talking about. (In Carcassonne, the English I heard were people from Viking Cruise ship tours.)
By next year, who knows what the situation may be.
Please remember that my experience is anecdotal and yours might be different.