The Ultimate French Ranch Desk

I found this at John Gregory’s showroom on Slocum St - always a good place to find treasures. It is a desk completely constructed from horn, from the 1920s, it was originally at the Arpel (as in Van Cleef and Arpel jewelry fame) home at the Place des Vosges in Paris. Rather surprising provenance, I guess that would be French horn. Anyone doing a French moderne ranch?