The Entrance to the Paris Métropolitain, an original architectural surround from the Paris subway system and an emblem of the early 20th-century art nouveau style, was installed in the National Gallery of Art Sculpture Garden in 2003. Designed by the pioneering French architect Hector Guimard, surrounds for Le Métro were fabricated from cast and wrought iron that was painted to resemble the variegated green patina of aged bronze surfaces.
Because all of the original Métro surrounds were installed outdoors, and many have been in constant use since the early 20th century, most surviving surrounds have been restored and repainted numerous times. As a result, the sculptural surface of the Gallery’s Métro entrance bore little resemblance to the surface intended by Guimard. By 2008, the existing paint layers were faded and chalky, and were actively lifting from the cast iron structure.