Tracked on 1 list across 1 authority.
Former nightlife hotspot turned Art Deco boutique hotel on Rue de Ponthieu near the Champs-Élysées; 25 individually designed rooms.
Description via Yonder-society.
Hôtel Mathis appears on 1 of the lists Mouga tracks, and written up on 1 more. Here's the full trail, dated and linked to each source.