which city to rent car when traveling to Normandy

After a long flight from overseas, I do not recommend that you drive from the airport to Normandy, you might be too tired.
But with a 1PM arrival, you are unlikely to be able to reach Caen (the main city in the area) by train before car rental offices close for the day...they tend to close at 6PM.

Not an easy situation, therefore... Maybe other posters will have bright ideas for you!

You do not state specifically, but may I reinforce balso´s point, if you are arriving CDG from a transatlantic flight, do not rent a car and drive anywhere.

Take the train to either Bayeux or Caen, stay the night and pickup your rental the following day. You’ll save one day of rental cost, and avoid driving unsafely.

Thank you,
We'll take the train to Caen and rent a car the next day.

I would recommend trying to confirm your reservation with the local rental car office by phone or email shorty before you fly or right after you get to CDG. Don't rely on the auto-generated email from the corporate office. We had a car reserved with Avis at the Rouen Gare last week and when we showed up to get the car our reservation had been cancelled with no notice or warning. We were fed a line about COVID limiting the supply of cars and were left stranded in the gare. We ended up using the Getaround app to get a car, but it was a hassle and the selection wasn't great.

Car availability from highest to lowest:Paris, Caen, Bayeux. In May 2022 I could only get a standard in Caen.

I've gone from Paris CDG to Caen to rent a car twice, but always landed early morning (7 or 930). This time we landed at 930 and barely made the last train to Caen. Very stressful day. No way you can get there landing at 1pm.

Bayeux is a much prettier place to stay than Caen. I find Caen very ugly. Also my father in law almost lost his mind trying to drive through caen with GPS and unexpected road closures in May 2022.

I still think best is CDG to Caen when landing in the morning. But afternoon landing I might just stay in Paris and train to Caen the next day if there's no rush. You will need some way to get to the hotel the first night, and that's easiest in Paris.

We rented a car from the Hertz in Bayeux and it was very easy. It's a short taxi ride to get there from town, but a relatively easy place to navigate. I agree with the idea of getting your train to Bayeux on your arrival day, staying there for the night, then renting your car the next day. It's a beautiful town and closer to the main Normandy sights than Caen. We just took a day trip into Caen to see the museum. It's a beautiful area!

The last train to Caen is at 9 PM on weekdays in the current schedule, so one would have to be very unlucky to miss that landing at 1 PM. Agree that Caen isn't the most charming city in France, but as a place to sleep, it will do!
Bayeux also works if you can find a car at Hertz there, but there are more car options in Caen.

Definitely stay in Bayeux if you have a car. We loved Chateau de Damigny, a few minutes out of town. We were treated with plates of crepes and eggs with 8 jars of homemade jams for breakfast. And the grounds are a delight.

We were minutes from the Normandy sites. Such a moving experience you will never forget.

One of the problems one can have renting from small offices is that cars with automatic transmissions are not much in demand by French renters. I would call the day before pickup to confirm that your automatic will be available at pickup time.