My sister and I just returned from 48 hours in Metz and Nancy, France, among other places. The Metz Welcome Center gave us directions to a local pharmany and we were able to have a Covid antigen test done, with negative results, that allowed us to stay in the country for 72 hours. This form/with code was accepted at the hotel and all restaurants and museums. It cost 25 Euros. Apparently they have not had many American tourists because the pharmacist said he had only tested maybe five Americans since the pandemic began.
If one is completely vaccinated and arrives by air from the USA, there is no testing required to stay in France. Your are only required to have proof of full vaccination, which for most Americans, is the CDC card.
Proof of vaccination is also required if your go to cafés, restaurants, museums, wherever people are gathered indoors, as well as if one rides the TGV or boards an aircraft (for EU destinations).
A concern for some tourists is having their CDC cards accepted, particularly at locations where staff may not be familiar with the card and may question its validity. The solution is either to obtain a recent Antigen test and showing the result or to find a pharmacy approved to issue an Attestation de vaccination based upon your CDC card. Pharmacies may charge up to 35€ for this service, a list is available here:
https://www.sante.fr/obtenir-un-passe-sanitaire-en-cas-de-vaccination-letranger
The Attestation has a QR code which proves vaccination or test results. The QR code can be read by an app called TousAntiCovid which reads these QR codes and keeps them in an easy-to-use format. The Attestion and app are often referred to as the pass sanitaire or health pass.
As of just a few days ago, the French government changed the validity period of the Antigen tests from 72 hours to 24 hours. In lieu of an Attestation de vaccination, you can still use Antigen test results to enter inside cafés, restaurants, etc., but you will now need daily tests which is time-consuming and costly.
Things are changing rather often right now, keeping up to day can be challenging but most protocols to follow are updated here: