When you enter via its grand staircase, you feel like Toulouse-Lautrec in search of tonight’s muse: The gilt-and-marble cellar dining room, awash in fin-de-siècle statements like platter mirrors and vested waiters, is a perfect piece of Paris off Piccadilly. This is not a crusty holdover but a pitch-perfect recreation out of what was once the Regent Palace Hotel, which in 1915 was the largest hotel in Europe. Menu choices are as authentic as Pernod, pastis, oysters, quiche Lorraine, and sublimely seasoned steak tartare (often, the first thing I order upon returning to town). The adjoining Bar Américain, a 1930s Art Deco treasure by an architect survivor of the Lusitania, does indulgently uptight cocktails and champagne, while its 80-seat cabaret, Le Crazy Coqs/Live at Zédel is an elegant venue that does matinees and evening shows ([£15–£35, no drink minimum). This bit of the Continental high life is not nearly as expensive as it looks, and its Gallic poise only adds to the deliciousness.