Normandy

You will need to take a train to Bayeux for this operator. http://www.bayeuxshuttle.com/ I used them this summer and they were excellent. About 120.00 US. You should book in advance and keep in mind Bayeux is about a 2 hour train ride from Paris.

If you do not take a tour, you will need a car. Normandy is huge (the d-day beaches themselves are 60 miles apart as the crow flies), and there is very little public transportation.

Here's an example of previous discussions of this frequent topic. You can collect a lot more with the Search box, top center.

https://community.ricksteves.com/travel-forum/france/day-trip-to-normandy

I believe the full-day Overlord Tour I took in the summer of 2017 cost either 95 or 100 euros. It's best to take the train from Paris to Bayeux the day before the tour. Ideally, you'd spend at least two nights in Normandy so you could do some additional sightseeing, but in a pinch you could probably return to Paris late on the day of the tour and spend just one night in Bayeux. On weekdays there's a 6:35 PM departure that you might not make (you'd have to retrieve your luggage from somewhere), then an 8 PM train.

I don't think day-trips from Paris are a particularly good way to do a D-Day tour. They mean traveling by bus, which is somewhat slower than a train, and that cuts into the time you can spend seeing the invasion sites. Most if not all of the tours run out of Bayeux are small-van groups, which don't waste as much time unloading and reloading at each stop.

Bayeux is probably your best bet really and there are a few ways to get there. This article has a great round up of how to do it https://www.rome2rio.com/guides/5-french-towns-you-need-to-visit/

Thank you folks for the helpful reply’s . Looking forward to Paris .