I have not been to France, but if it’s anything like Germany, booze-wise, there are plenty of things sold there that never make it to the States, never mind your particular state or neighboring states. If you like apples, why not ask for some Calvados?
I go to France at least once a year for business and I always stock up on gourmet food gifts. You mentioned not being able to bring back cheese due to restrictions, but there are none except for some special cases. I always pack several kinds in my suitcase as there are so many varieties you just cannot get outside of France. This goes for wines as well. Sure you can buy Bourgognes and Bordeaux wherever you are, but there are many gems that don’t have enough production to make it outside of their local area, let alone France.
If you like tea, get something from Mariage Freres or Kusumi tea. The latter is famous for their decorative tins. Both offer teas that are only available for their domestic market.
If you like chocolate, Alain Ducasse and Au Chat Bleu are not available outside of France. Alain Ducasse is only sold in two locations in Paris.
If your husband doesn’t have time wandering around from shop to shop, have him visit the gourmet section of Galleries Lafayette in Paris for one-stop gourmet shopping. Olive oils, balsamic vinegars, smoked and flavoured salts, anything with truffles in them (not infused) are just some of things that can be picked up rather inexpensively.
You mentioned Normandy and they are known for their apples and dairy products. You can pick up a nice bottle of Calvados or a special camembert that’s been wrapped in herbs.
If you want to get away from food, my wife’s friends and the girls at my company’s reception always ask for L’Occitane products. Again, you can get them outside of France but the domestic prices are invariably better. Some products will have a domestic launch first, although you’ll probably be able to get them if in the USA if you wait six months or more.
If you want more of a keepsake, have your husband walk along Champs-Elysees and have him visit one of many luxury brand shops. Prices are usually, (not always), better than what you would get outside of France. A few years ago I bought my wife a Baccarat vase for about 30% off of what it was selling for in Japan. Hermes also has exclusive scarf patterns that you can only get at the Champs-Elysees store, (or maybe only in Paris, I forget).
Tell your husband to avoid shopping in the duty free shops at CDG. The items they have there are total rip offs and it will be hard to find good deals. The Chinese come in droves and impetuously buy whatever crap product they offer and consequently drive up prices. The only time I buy at the airport now is to maximize the number of wines I can take back and emergency gifts in case I forgot to buy for someone.
Direct your husband to Maison Georges Larnicol in Paris. It’s one of my favorite stores there. They sell Kouignettes, which are the most delicious entity I’ve ever eaten. They are better than sex. They are about 3" in diameter, and made with slightly salty caramelized butter and real sugar, and they literally melt in your mouth. They are extremely rich, and you won’t need to eat more than one. They come in several varieties, all delicious. Have your husband try one when he’s there, so he’ll know just how good they are.
I’ve brought them back myself from Paris, and they are just as good after surviving the long flight.
A piece of Quimper pottery, it is made in Brittany and should be easy to find in St. Malo.
From Normandy a bottle of Calvados. It is sold everywhere in Normandy and the good stuff is hard to find in the US. Wrap the bottle in clothes or towels for safe transport.
Thanks everyone - great stuff! He’s a got a list packed and ready to go - we’ll see what happens. 
Stick with the classics: Tennis balls.
So I thought I’d post back to this thread showing the swag I actually got - your suggestions were very helpful to the husband, so thank you again!
The first item is a very nice quality dish towel, printed with pictures of a selection of cheeses made in France. At the bottom is a quote (in French, of course) from Charles deGaulle, saying “A country with 325 varieties of cheese is ungovernable.”
There’s also a beautiful cashmere scarf (super soft), a pillow cover with a stylish lady and Greyhound on it from the Eiffel Tower in Paris, and from London there’s a tin in the shape of one of the classic red phone booths that has tea in it. There’s a notch cut in the top that allows you to use the tin as a coin bank once the tea is gone, which I think is just brilliant - cute and also very useful.
I know I’m too late but in case anybody else reads this I’d suggest cheese. In the US young, unpasteurized cheese is illegal to sell but it’s permissible to bring in for personal use. I’d possibly suggest a young, soft cheese like St. Andreas. The downside is that it is perishable.