A 3,000m2 garden, an Empire-style living room that's listed as a historic monument, and an asking price of €250m. The Hôtel de Rohan-Montbazon, situated at 29 Rue du Faubourg-Saint-Honoré in Paris's upmarket 8th arrondissement, just a stone's throw from the Chanel, Hermès and Loro Piana boutiques, is causing quite a stir among the city's small circle