The Metropolitan Museum of Art in New York City has a wonderful Parisian Art Nouveau interior known as The Wisteria Room displayed in a little side gallery cove off of the main 19th century European galleries. It is the only complete French Art Nouveau room interior displayed in its entirety in an American Museum (I believe Whistler's Aestheticist Peacock Room is displayed at the Smithsonian).

I often go stand in the room when I visit the Met -- it's got a beautiful dark soothing ambiance I can't get enough of. I wish I had a room like it.

From the placard: 

Wisteria Dining Room, 1910-14

This dining room comes from an apartment in Paris at 10 bis, avenue Elysee-Reclus (at the foot of the Eiffel Tower), created for Auguste Rateau, an engineer, member of the French Academy of Science, and connoisseur of the Art Nouveau movement. The interior decoration of the apartment was conceived with each room a distinct and unified whole. The work was carried out between 1910 and 1914 under the artistic supervision of Lucien Levy-Dhurmer, a ceramicist, who about 1895 turned his hand to painting and decorating. 

Wisteria is a symbol of welcome, and Levy-Dhurmer incorporated it throughout the room: the murals, painted in the Pointillist style, depict herons and peacocks standing in wisteria-laden landscapes; the walnut-veneered wall panels are inlaid with purplish amaranth representing clusters of wisteria blossoms; further clusters of blossoms and leaves are carved on the furniture and stamped on the leather upholstery. Wisteria even appears on such elements as the door handles, the drawer pulls, and the gilded details of the fire screen. The bronze-and-alabaster standing lamps evoke the twisting trunks of wisteria vines. 

This is the only complete French Art Nouveau interior on display in an American museum. 

Following are shots illustrating all of the major features of the room, which are uniformly inspired by wisteria branches and flowers - from the wall motifs to the lamps to the chair and table details.