So, after looking at them some more, I'm pretty sure those French retailer listings are just old junk placeholders, and when they say Switch, they do mean Switch, not Switch 2.
The IDs in the URLs, like a18445259, are all sequentially next to many other placeholder listings for the same publisher but across all consoles -- Xbone, XSS/X, PS4, PS5. Switch. If you go far enough, then there could be a non-placeholder game from the publisher, and I think this is probably how that Twitter poster claimed identifying what games the placeholders were for. For example, go back from a17138976 (PREREF BANDAI SWITCH 12) to a17138972, and you'll see Tekken 8 for Xbox.
I don't think the listings were new, and even if they were, a dozen of them have been added for every console for each of the publishers in question, so they definitely don't represent an upcoming slate of games to be announced for Switch 2.