Adding on a trip to D Day beaches from Paris without a car?

The dilemma with seeing the D-day beaches is the shear size of the beach and beach area -- it 50, 60 miles east to west and another 25 miles or more deep and there is no public transit from site to site. Without a car, you need to take a good guided tour. Paris too far since the travel time would eat up a half day or more. I would overnight in Bayeux or maybe two and take a day tour from there. You might want to review this recent posting ---- https://community.ricksteves.com/travel-forum/day-tours/high-praise-for-tours-of-mont-st-michel-and-d-day-sites-with-overlord-tours

Taxi from CDG to St Lazare is easy and most convenient. Train to Bayeux is a regional one so can buy ticket at train station.
When you say "beaches" are you interested in the D-Day areas like Juno, Sword, Omaha, etc? If so best to go with a small tour that will provide transport to/from.

Looking online there are guided Day tours of Normandy Beaches from Paris with Lunch starting at just over $160.

We are actually doing this September 2., ( I can’t comment on if it works the way I think it will) . We arrive at CDG Sat morning . Trying to decide if we take a taxi , bus or Train to Gare st. Lazare. We then catch a train to Bayeux and are staying near the station. We are signed up to take an all day tour with Overlord. We will stay 2 nights in Bayeux and then catch at 7:30 ish train back to Paris . We should not need any taxis once in Bayeux.

To spend 2 full days sightseeing in Normandy, you would want to spend 3 nights there. Day 1 would be getting from CDG to Bayeux. This can take 6+ hours when you factor in passport control, getting from CDG into Paris (if by train, you will arrive at Gare du Nord then need to walk or take the RER to Gare St Lazare), the train to Bayeux, then getting to the hotel. You may not wish to do this after an international flight. Maybe add a few days after the tour for this?

Day 2 would be your first day touring the DDay sights. There are a few companies that offer tours from Bayeux. Overlord is one of them that gets good reviews here.

Day 3 you could take another tour, or see the tapestry and go to the DDay museum in Bayeux.

Day 4 you would return to Paris.

There are several apps for taxis in France. We have used G7. You could also ask your hotel about options.

Thank you all for the great and prompt replies. Thanks for the links. I plan to take a guided tour once I get to the area. Thank you for the information about Overlord, I had not heard of that company. To the person going Sept 2, give me updates of how well it went. And would you mind telling me which hotel(s) is/are near the train station?
Thank you very much!

I don’t know where the Bayeux train station is since we had a car. I don’t think you have to worry about safety in that area. The locals love Americans.
I recommend our hotel, the historic Lion d’Or which has connections to WWII military leaders who had stayed there.
We loved seeing The Bayeux Tapestry.

The recommended hotels aren't near the train station, I think. I stayed at the Hotel Churchill and really liked it. There is another one that people recommend too, I am sure someone will come along and mention it.

Yes you can do this ! And though they are a bit expensive, the guided tours -- especially by a company like Overlord -- are worth every single penny and will absolutely enrich your experience.

We have stayed at the Churchill and the d'Argouges. Both are within walking distance of the Bayeux train station. With that said, in 2019 we had the d'Argouges staff arrange for a cab to take us to the train station because it was raining. Otherwise we would have walked.

Overlord tours meet up in the square directly behind the Churchill, and, at least for us in 2019, they picked us up at the parking lot across from the d'Argouges. Bayeux is small enough that you can walk anywhere - and safely.

If you will be in Bayeux on a Monday night, ask your hotel to make a restaurant reservation for you. Many of the restaurants are closed Monday nights.