I'm not sure of the situation in France, but this is starting to happen readily on Amazon. Lots of physical books you can buy that are completely AI-generated nonsense.
I should have been clearer; it's not just ebooks that are exempt, but anything without an ISBN. You can make a paper book with Amazon print-on-demand that doesn't have an ISBN, and then you don't need to send it to the dépôt-légal.
Many people argue this is bad and should be changed. But it's debatable.
According to https://www.bnf.fr/fr/depot-legal-pour-quels-documents, pure ebooks are not exempt; they are just archived directly from the distribution platforms by sampling.
What scares me is that some mixed works (PDF/on-demand prints) are not archived because the authors think the system is too clunky to deal with, which is really a shame for books like https://laurent.claessens-donadello.eu/pdf/lefrido.pdf, for example.
But ebooks are exempt from it. (Ebooks obviously didn't exist in 1537 but they've now been around for decades.)
So unless AI is used to make books published via traditional publishers (which is of course possible, but somewhat unlikely), the situation doesn't change much as regards to archiving books (in France).