Normandy

You have to book the Eurostar really early in advance if you want the get a low price. This the official site https://www.eurostar.com/us-en and there are no others less expensive. You could fly for cheaper in some cases.

It is also possible to just take a train to Bayeux and pick up a tour there for the Normandy beaches if you are looking to save money. Here is the link to a company many use for Normandy D-Day tours https://www.overlordtour.com/

In reference to the Eurostar, tickets go on sale 6 months in advance of any given travel date. Just like airline tickets, train tickets typically cost more the longer you wait to purchase them. I find tickets for the morning of October 26th at 102€ each which I do not consider all that expensive for travel little more than a month away. You could look at airfare but you´ll probably pay a lot more considering you´ll need transportation to/from airports.

With only 3 full days in Paris, adding a trip to Normandy adds a good amount of expense and really cuts Paris short. I am not really one who likes to spend all day in a tour bus though there are companies which offer this service. One possible option would be to leave Paris a day early, spend the night of the 29th in Bayeux or Caen, and return for a late Eurostar departure on the 30th.

What you are proposing is like going to a long wedding in Philadelphia, and taking a same-day trip to New York City. It may seem desirable, but there's a huge cost in dollars and in what you called "your time."

Your topic is often proposed here, so you can see several solutions using the search box, top center. It's really nice that you were able to add Paris to your family visit in London. But it sounds like you have to go back to London to fly home, when you could have gone home from Paris. That's another two to three hours you'll never get back.

Paris is a magical place, and it's too bad you'll have to give up time there (and NEARBY excursions, like Versailles or Vernon) to run-out to the D-Day Beaches (Normandy is really, the name of a much larger tourism destination.) This newsboard has a lot of Independent Travelers, which means that door-to-door daytour packages (I mean Paris-D-Day-Paris) are not a big part of the most experienced reports here. There are a lot of people who want a well-informed guide, or to avoid renting a car while independently traveling to Bayeux for one night, and you do get good information about companies that can pick you up at the train station and take you around. But these tend to be expensive, and you MENTIONED thrift in your OP. The cheapest way to do the Bayeux area is on-your-own, but with a rental car.

There is no substitute for the D-Day beaches. But it's not as if there's a lack of "history" (referring to your husband's interests) elsewhere in France. I'll just describe one tiny, tiny example (the point is, it's not an isolated thing.) We like gardens, so on our eighth trip to Paris, we went to the Parc Floral, when it's appropriate to include Chateau de Vincennes (which is otherwise, not a must-see.) Walking to the Parc from the Chateau, we passed over an empty traffic triangle with a long inscription in French on the stone. It seems there was a German invaders war monument put up there during World War I-they got really close to Paris. The French tore it down and put up a French monument after the war, so when Paris was occupied by the Germans again, the occupiers tore down the French monument and rebuilt theirs. When Parisians tore down the second German monument, they decided to leave the pedestal empty, as a remembrance of what happened!

The WWII Surrender Museum in Reims might be a better choice for a day trip with the limited time you have in France. And you could throw in a little champagne in addition to some WWII history.

Reims is just a 46 minute train ride from Gare de l'Est.

My family also looked into visiting the D-Day beaches from Paris when we planned a three-week four-city trip to Europe in 2013. As others have posted here, you will spend a significant amount of time getting to Normandy. We decided to spend five nights in Bayeux, Normandy and save Paris for another trip. And we splurged on a very thorough 2-day tour by Dale Booth of the American beaches. You and your husband may have different interests and priorities. Day trips from Paris have been mentioned in this forum (for example, https://community.ricksteves.com/travel-forum/france/d-day-normandy-tour-for-the-day-with-round-trip-transportation-from-paris)

I don't know how often it is offered, but Overlord has a full-day tour that departs from the Bayeux train station (rather than the usual pick-up point downtown) just enough later that it is possible to take an early train up from Paris the same day.

When I was in Paris it was during the train strikes so the only way to do the tour without worry was taking a bus there. I did the CityWonder tour. I had a great time and felt it was worth it. It is a long day, you check in at 6:45 am and get back around 8:30 pm. Lunch is served and you stop at a gas station for snacks and bathroom coming and going. You leave from Palais de Chaillot, at the Trocadero. It starts at Utah Beach. You then go for the Cider tasting (passing by the German Cemetery). After Cider you have lunch then on to Pointe du Hoc, then the American Cemetery above Omaha Beach. It wasn't listed in the tour but we did stop at Omaha Beach for a brief visit before returning to Paris. At present they are offering this tour for $201 each so it isn't cheap, but you don't have to deal with the trains.

I did the Eurostar directly from their site but I did it 6 months out.

Felice,

Taking a day trip from Paris to Normandy is not ideal due to the travel time involved. The number of sights will be limited by the time constraints. However day tours are offered but it will be a long and probably tiring day, and somewhat expensive. This is one option you could have a look at. You'll need to pre-book the tour.