Scattered throughout the streets of Paris, the elegant Art Nouveau entrances to the Métropolitain (Métro) subway system stand as a collective monument to the city’s Belle Époque of the late 19th and early 20th Centuries. With their sinuous ironwork patterned after stylized plants, the Métro entrances now count among the most celebrated architectural emblems of the city; however, due to the city’s wariness in the face of industrialization and architect Hector Guimard’s decision to utilize a then-novel architectural aesthetic, it would take decades before the entrances would earn the illustrious reputation that they now enjoy.
Paris’ radical transformation from medieval labyrinth to Second Empire metropolis between the 1850s and 1870s coincided with the construction of London’s first underground railways. Although the flurry of demolition and reconstruction taking place in the French capital would have been an ideal time to install a subway system, Prefect of the Seine Georges-Eugène Haussmann had no apparent interest in implementing such a scheme. The state and local governments argued over who would be in charge were the system built, while the public—horrified at the thought of their city being swallowed up by something so industrial—expressed their ardent disapproval.
Ultimately, it took the Exposition Universelle of 1900 to convince the city it needed a modern subway transportation system. Charles Garnier, the architect best known for designing the Paris opera house which now bears his name, advised the Minister of Public Works that in order for the people to accept the Métro it would have to be seen as more than an industrial creation – it would have to be a work of art. With this in mind, the Société Centrale des Architectes held a contest to select an architect to design the Métro’s aboveground entrances. Although the firm Duray, Lamaresquier, and Paumier won the competition, the selection was overruled by Adrien Benard, the president of the Conseil Municipal de Paris; in their stead, he chose Hector Guimard, a noted Art Nouveau architect who had not submitted for the contest.
A graduate of the Paris École des Beaux-Arts, Guimard was fascinated by Eugène Viollet-le-Duc’s theories of structural rationalism, if not by the the Gothic architecture Viollet-le-Duc so admired. Blending this inspiration with the influences of the British Arts and Crafts Movement and the Art Nouveau work of Victor Horta, he developed his own form of Art Nouveau rationalism – one which stood apart from the eclectic, Classicist proposals made by his competitors and ultimately won Adrien Benard’s interest and approval.
Rather than the masonry designs presented by the winners of the competition, Guimard instead proposed that the Métro entrances be built in cast iron and glass. The decision had several practical benefits: most significantly, iron entrances took up far less space than stone, a necessity in many of the chosen sites for Métro stations. Iron was also cheaper and easier to produce and transport, and allowed for greater ease of mass production than masonry.
Beyond these logistical concerns, cast iron was also far better suited to the sinuous, naturalistic and slender curves that embody Art Nouveau. Using a set of modular structural elements, Guimard created five entrance types, ranging from simple railings to lavish covered pavilions; each station entrance shared the same green paint (meant to resemble bronze patina) and a sign bearing the word Métropolitain in a typeface designed by Guimard himself. The simplest and most common variant was a set of railings with a pair of amber-colored lightbulbs shaped like flower buds, their tinted light illuminating the Métropolitain sign mounted between them. The greatest sensation, however, was in response to the elaborate pavilion entrances, with their fanned glass awnings crowning the stairways beneath.[6,7]
Although they are now celebrated as an iconic element of the Parisian cityscape, Guimard’s Métro entrances were initially met with contempt by irate Parisians, who pronounced the unusual font on the signs “un-French” and the faux-patina green to be “German.” By 1904, 141 stations had been built using Guimard’s five modular variations. The latest version for a station adjacent to the Opéra Garnier, however, was rejected by the Conseil Municipal, which declared its style to be incongruous with the existing architectural traditions of the city and therefore inappropriate for construction next to the Opéra.
Only 86 of the original 141 Métro entrances now remain, with many having been demolished in the decades before Art Nouveau was recognized as a style worthy of preservation policies. Those stations that do remain are now seen as the inspiration for the eponymous Métro style, their verdant ironwork and elegant lettering irrevocably associated with the entire visual branding of the Métro system. Despite the short-lived prominence of Art Nouveau and the initial disgust of the city’s residents, Guimard’s remaining Métro entrances have—like their distant cousin, the wrought iron Eiffel Tower—become an integral, even beloved, symbol of Paris.
 Ayers, Andrew. The Architecture Of Paris: An Architectural Guide. Stuttgart: Edition Axel Menges, 2004. p381-382.
 Ayers, p382.
 Sennott, R. Stephen. Encyclopedia of 20th Century Architecture. New York: Fitzroy Dearborn, 2004. p840.
 Curtis, William J. R. Modern Architecture Since 1900. 3rd ed. London: Phaidon Press, 1996. p58-59.
 Sennott, p840-841.
 Ayers, p382.
 Sennott, p840.
 Ayers, p382.
 Sennott, p841.
 Poulin, Richard. Graphic Design Architecture: A 20th Century History. Beverly, MA: Rockport Publishers, 2012. p45.