This hotel in the heart of the art gallery neighborhood Saint-Germain, with its 20 individually designed rooms and suites, was once a haunt of figures like Oscar Wilde, Salvador Dalí, Grace Kelly, and Frank Sinatra. Prize-winning French interior architect Jacques Garcia is behind the hotel’s current design, dominated by patterned wallpaper, marble columns, and opulent fabrics. The underground vault was transformed into a Roman-style thermal bath, complete with pool and hammam.