I want to travel to Paris, in March. Mature solo frequent traveler.10 days.

For a "reasonable transfer" from CDG to Saint Germain des Prés or Île Saint Louis (is that the little island you had in mind?), you can take the suburban train (RER B) for 10-12€ to "Saint-Michel Notre-Dame", which is walking distance to Ile Saint Louis and not that far from St Germain des Prés either (or you can transfer to metro line 4). It requires that you are able to carry your luggage up a flight of stairs (there is an elevator at Saint Michel, but it does not work 100% of the time, and escalators don't reach the surface).

Or for 57€, you can take a taxi. Actually, to Ile Saint Louis it could be 53€ - the fare depends on the side of the river, and I don't know what the policy is for the islands.

The city is very quiet at present and should stay so: tourism from Asia has not resumed yet, and numbers from other regions are still down.

expect it to be showery and cool -- perfect time of year for a trench coat and layers.

Cab fair is baed on the arrondisement and I believe Isle St. Louis is in the 4th which is on the right bank and hence 53 for cab fare. If you take a cab have the address WITH zip code written to hand to the driver with 53 Euro on the sheet. St. Germain -- (no e -- he was a guy) is 57 Euro. Train is 10.30 and as noted above you have to be able to carry bags up and down steep stairs if you will use the metro. RERs have elevators but the metro almost always involves several steep flights of stairs.

I usually take a taxi after the overnight flight and do as Janet suggests with the full name and address of my hotel written on an index card I can just hand to the driver. If you go with a taxi, follow the signs after you come out of Immigration/Customs to the taxi rank. Don't go with anyone who comes up to you and asks if you want a ride. I'm not sure how prevalent this now as they are restricting entries into the terminal building so that is kind of keeping the scammers out (or was in October, lol).

I'd have a waterproof rain jacket with a hood. You may still have some chilly days. I was in Paris the end of March in 2019 and was fine with a puffy vest, long sleeves and a waterproof outer layer although many locals still were wearing wool coats on the Metro. I'm pretty cold tolerant so this will kind of depend on your particular resistance to cold! Do you mind sharing where you live?

I saw you had a thread from November regarding Covid testing. Did you see the thread from Kim that France has dropped the Covid entry tests starting yesterday so you will not have to worry about this. US still has the requirement but they are exceedingly easy to get in Paris - just go to a pharmacy near your hotel.

We've stayed at the Hotel des Deux-Iles and will do so again. It is as centrally located as can be on Ile St. Louis There are also a couple of other hotels on the same street. Cross the river and you will be in the Marais -- cross it the other way and you'll be in The Latin Quarter. Walk to the end of the island, cross the bridge, and you'll be at the back of Notre Dame -- such as it is now as some of the immediate area is closed off. The Metro is near enough that getting anywhere is not a problem. If you stay there we can tell you about a great breakfast place nearby as the hotel breakfast seems a bit overpriced for what it includes.