> I'm not entirely sure what "livres de collections" are, but in context it seems to mean fancy hardback editions of works, like those put out by the Folio Soci

> I'm not entirely sure what "livres de collections" are, but in context it seems to mean fancy hardback editions of works, like those put out by the Folio Society [2]. It doesn't just means « fancy », but also old and rare. In a French speaking context, loose Pléiade prints (the default « fancy » edition) might not gather much interest unless it's sold as a whole collection. On the other hand any good quality early edition of the well known writers of the 18th or 19th c. is worth at the very least a few hundreds. If you have a first edition print of any of Jules Verne's books by Hetzel, that's worth tens of thousands. A full copy of the first or second edition of the Description de l'Égypte is worth hundreds of thousands.