We arrived in CDG on Sept 7 and customs did not ask for Passe Sanitaire nor CDC card. We took TGV to Reims and no one asked us for proof of vaccination either.
First time our vaccination status was checked was at our hotel and our CDC card was sufficient. All restaurants require proof of vaccination as well and our CDC card was accepted at the first 2 restaurants we went to.
However, we walked into a pharmacy in Reims and were able to obtain a Passe Sanitaire QR code using our CDC cards. It took about 10 minutes and cost us 4 euros each. The Passe is on paper and can be uploaded to the “TousAntiCovid” app, which makes it easy to show. We are traveling to Spain next week and feel a lot better having a Passe Sanitaire. Hope this helps!