My wife is a Francophile, and her biggest thing that she would want is
romance, in the sense of Romantic Fantasy, or general Romantic Fiction, from a strongly French inspired setting.
That, and fashion, especially where it isn't at all necessary.
Like, forget the movies, the historical musketeers wore
this:
So, you have early firearms with names like the dragon and falconet, used by a guy who also uses a sword, more heavy chevalier, and dragoons in between. Overlay all of that (sub in fancy crossbows with animal heads at the ends if you don't like guns in dnd) with all the dark mystery of catacombs and ancient pagan sacrificial sites, and just everywhere the juxtaposition of beauty, danger, mystery, honor, poetry, war, and deeply emotionally loaded internal conflicts over religion, art, politics, and always,
always, romance.
Also play Dragon Age Inquisition.
Now, when we add dnd to all of the above, and ask ourselves, is there a Basque analogue? Are there neighboring peoples with whom the Francofacsimile people have dynamics similar to the Franco-Spanish and Franco-German borders, or the history of Roman conquest and unrest? Are there active heretical communities? Are there regions that still follow the old ways but the closer you get to the urban centers the more people practice the new faith?
Remember that the French gave us
le morte d'arthur, musketeers, cafes as a popular western concept, the "kill them all, the lord will know his own" quote, and lots of other interesting things.
just a nearly limitless pool of inspiration.