Language from Wikidata (Q467897), property P407 "language of work or name", via the English Wikipedia article already linked on this record. The field was empty. Wikidata gave a single value, "French", which maps to findopera language row 3.

Librettist from Wikidata (Q467897), property P87, via the English Wikipedia article already linked on this record. The field was empty. Wikidata occasionally lists only one of two co-librettists, so this may be incomplete rather than wrong.

Wikipedia article: https://en.wikipedia.org/wiki/Les_diamants_de_la_couronne