Very meaningful gift for French family

It's very hard to select a gift for someone you don't know since you can't know what's "meaningful" for them. I think a heartfelt letter would be a good start because it's personal, and it will likely be appreciated (I don't think you can go wrong with that). The French have access to the best food and wine in the world, so that's probably not a good option. Your son may also have some insight into what they would appreciate, much more than strangers on this forum, I would suspect. I would ask him and go from there.

A fine Kentucky bourbon is always welcome.

Are they in a city apt or have a house/yard? If the latter, you could plant a tree or flowering shrub, together, and/or an engraved stepping stone? Or maybe if it's a patio size. Logistics of a nursery and etc may be a challenge, so maybe a donation to a relevant charity?
I have done both for that magnitude of thankfulness when a "thing" is just not right.

Your son knows them so is the best person to give you a steer.

Check this out Charlene: https://www.davidlebovitz.com/food-gifts-to-bring-french-people-from-america/
A couple of people have suggested making a donation to a charity in their name. Charities aren’t as common in Europe as they are in America.

karen’s suggestion is a great one.
I would also take them to a very nice restaurant for dinner.

Does your son have any suggestions?

You could always wait and buy something in Paris for them (e.g., a more expensive bottle of French wine than they might normally purchase for themselves or an expensive champagne).

Not knowing what your budget is, but in light of they literally saved my son's life and he has lived with them for 6 months, is treating them to a week at their favorite vacation location within your means?

This isn't easy.
Charity donations are not given as gifts in France. That's a part of American culture and tax structure that would leave them confused and thinking you are cheap, a mis-impression. Sorry folks but it's a big cultural différence.
A bottle of fine wine could have them trying to share it with you, no matter how much you stress that it's for their cellar.
If your son confirms that they drink cocktails, then a fine bourbon might be appreciated. But as you said, how can that equate with saving his life
Bringing a good or fine bottle of champagne would mark the occasion of the meal you are sharing, and be another good start.
The problem with wine, bourbon, and champagne is that they are gifts that are here and then flushed away. You want your gratitude to last longer.
Otherwise, how about an heirloom from your own personal collection or family to say thank you from your family to theirs.
I also think the letter or handmade gift would convey your message.

Not that this would be feasible, but would they ever be in a position to visit your family, even if not for 6 whole months? A genuine invitation could be meaningful on some level.

Regarding maple syrup, a friend named Rosa Jackson, who splits her time between Lyon and Paris, running cooking schools, is actually from Canada. She says she can’t get by without maple syrup, so always has a supply on hand. I’m not certain how she gets it, and she likely has acquired more of a taste for it than someone not so familiar with its unique sweetness, but it would at least be a token to include with your visit. You were probably going to bring some already, and it’ll probably be very well received.

I think you can consider a set of gifts but I don’t know anyone French, so disclaimers abound on the applicability of my advice. 😅

One, assuming that he had planned to live with the family (unrelated to their saving his life) I think that you could consider some edible food items and traditional gifts from the US or Canada (I’m not clear where you’re from as you mentioned Maple Syrup, could be Vermont). Bourbon, maple syrup, Tabasco, whatever is local to you, pepper jelly, whatnot.

For the special family to family gift for the care they’ve given your son, some ideas that I have are along the “meaningful” route - a heartfelt note, a engraved framed picture of everyone together, a cutting board engraved with a family name, a small figure, an etched glass pitcher, a family monogram to hang on a wall (I live in Columbus, Ohio, and Fortin Ironworks is popular around here and does beautiful work, their website might give you some ideas).

We found maple syrup to not be rare in Europe, but its not a common dietary item so they might not know what to use it for. Various American spirits are pretty available too, just expensive. Ask your son to do some detective work and figure out what might be something appreciated, but I think taking them to a very nice dinner would be a good start.

I've been reading the wonderful comments you've been receiving and am struck by how much we want to find the perfect gift to thank someone for saving another's life. It just can't be done. They will see it in your face when you express your feelings and deep gratitude to them. Beyond that, you, of course, want to give something tangible to them. I hope that your son can be helpful, but some kids no matter how wonderful they are. . . Perhaps when speaking with your son's French family, you will learn about their likes--theater, cooking, art, museums, football, etc. If so, and if within your budget, season tickets? Tickets to one event? Le Creuset? Copper from Dehillerin? A nice dinner out with all the trimmings? Please, please don't keep us in the dark! I'd love to hear the ending (or maybe this is the beginning of a friendship.)

Do any of you have a creative talent? If so, give a gift of your creation with an appropriate label or note written on it? I'm a quilter, so would bring a table runner, or lap quilt. Quizz dear son as to colour choices or if considering an art piece, something related to their interests.
I was going to suggest taking them out to dinner, but who knows what will be allowed at the time.

Pay good attention to Bets’ suggestions. She lives part time in France, is married to a Frenchman, and is very well acquainted with French manners and culture.

Since they have been restricted from Covid to travel this past year, I would consider a gift certificate to a European hotel chain where they could choose a destination, along with a beautiful hand-written card of gratitude.

Gifts to charity (unless a family specifically requests to commemorate a loved one etc) are NEVER 'gifts' in the US either -- never do this.

Hard to beat the lovely letter -- and then take them to a really nice dinner -- maybe a Michelin level restaurant. If it is a bottle of wine you want to give, make it an excellent American wine not a French wine -- they have those -- people who enjoy wine are usually open to exploring excellent examples from other cultures that they can't easily obtain at home.

And foodstuffs like maple syrup or peanut butter are gauche -- if they want it they can buy it in France and they are not sufficiently luxurious to be a gift to someone you don't know. A bottle of wine is almost always good -- not as the only gift in your case -- but as an initial offering. Once you get to know them and see their home, you might have an idea of something you could send afterwards.

I’ve never understood the american obsession with shoving peanut butter on the French. The product isn’t that hard to find anymore and it just doesn’t seem to be to the taste of the French.
I also echo Bets.
I would suggest something local from where you are from. I live in Georgia, so I usually give a nice tin of pecans. Artisan chocolates or candies would be appropriate too. Wine does not make a good gift fir the French as they will feel obligated to serve it and they have already licked out the wine for your meal. But a local alcohol from where you’re from would be a nice touch.

The more I think about it the more I think it should be a staged thing. You don't know them or their home, so you don't know what would be 'perfect'. So a lovely US wine and taking them to a lovely meal at a fine restaurant might be a think you do on meeting them AND then once you have seen their home and gotten to know them a little, you can send the letter and the 'thing' you think they would love.

If people visited us they might decide to give us some elegant unique champagne glasses as we have a sort of collection of different ones we always use for aperitif which is always champagne in our home. All of ours were broken a few years ago in a minor household disaster and so we are rebuilding the collection. But for someone else that would be 'meh' --- Maybe they have particular interests you could add something to.

Maybe you have steak dinner at their home and notice that they have ordinary steak knives -- in France you can buy exquisite sets that might make a nice gift with lovely wood handles. Or since if you have dinner with them you will bring flowers, you can check out the vase situation and a lovely vase might be welcome. Or perhaps you learn they have a particular interest in music or theater and could give them tickets to some amazing thing.

OK, so who doesn’t put maple syrup on their French toast?

Wine works because it is generic but can be fancy. Liquor is trickier unless you know they drink it. Very nice candy is fine. But these are modest hostess gifts -- finding the just right more elaborate gift requires knowing the people you are visiting.

Now that the 'clutter' has been removed hopefully OP will return and let us know if any of this helped. Or if still searching will provide a budget to help focus the serious suggestions.

I am really appreciative of the helpful suggestions I received here in response to my “meaningful gift” question. Since I tend to overthink things, I kept coming up with reasons why this or that wouldn’t be perfect:

• I liked the idea of a family heirloom, but my octogenarian parents are in possession of all of those...
• I liked the idea of an engraved pitcher. My son even explained that the pitcher his sponsors use at dinner is damaged. But the couple have two different last names (I could put one name on each side of the pitcher? LOL). Then I thought of a non-engraved crystal pitcher, but they are very health conscious and I thought they may not want to drink from leaded crystal. Then I looked at lead-free crystal, but discovered that the higher-quality stuff is often very fragile. So, I looked for thicker glass. It fell apart when I was finally looking at Cost Plus extra-thick margarita pitchers from Mexico. There is nothing wrong with them (I decided that I want one myself), but I don’t think it is their style and I wanted something more substantial than an everyday houseware.
• I liked the idea of something custom made. I thought of making the mom a pair of earrings, which I still may do, but that is a gift for only her.
• I had thought of art before, but that is so subjective. For example, I love stained glass and we have some excellent stained-glass artists near me. But, who knows, maybe they don’t like stained glass. You just never know.
• A Michelin restaurant sounded like a good idea, but when I looked online, the “budget” one was $250 per person, which is out of my price range, as they have a large family. I wouldn’t hesitate if I could afford it.
• I gave them Kentucky bourbon when I first met them in 2016.

Perhaps I’m asking for too much to get a very personal gift for someone I don’t know well.

In the end, I decided on a jar of great and maybe unusual jam, a dinner at a non-Michelin restaurant and a vase from artist Michael Aram]1

My son noted that the mom often has flowers in the sink, but he doesn’t know where they end up; maybe the bedroom. I think it’s a pretty likeable vase, for many different tastes.

Thank you so very much for all of the thought you put into helping me. I really appreciate it!

That vase is beyond gorgeous!

Lovely vase, and glad you made a plan. And thanks for coming back to tell us. Have a great trip.

Agree! Go with the vase. It's simple, classic, and stunning.