I will arrive at CDG Terminal 2 and will be going to Lyon via CDG TGV. I assume that I need to have my US CDC vaccination card converted to the French health pass prior to getting on the train. There is a pharmacy in 2F that can do this. Will it be possible (and easy) to get to the pharmacy directly after immigration and then go on to baggage claim? Or is there some other way to do it? I would really appreciate if you can advise me about the logistics for this. Thanks.
If you're flying in from overseas (outside of EU/Shengen), once you deplane, you will immediately go to immigration and then descend straight to baggage claim (unless you're transiting). I don't believe you will be allowed into the departure gates areas where you can mix with other departing passenger areas.
So I believe you would need to claim your baggage first before visiting a pharmacy, since the baggage claim area is one-way (exit only) and is just after immigration.
Once you've collected your bags and exited the baggage area, you will be free to roam around the non-secure areas of Terminal 2 and visit pharmacies at CDG (before security).