The Paris Métro entrance designed by Hector Guimard first appeared in 1900.
Guimard’s entrances were created for the opening of Paris’s first Métro line, which began service in July 1900 in time for the Exposition Universelle. Their cast-iron railings, organic curves, glass, and distinctive “Métropolitain” lettering made the entrances among the most recognizable public works of French Art Nouveau.
The earliest installations were not all completed at the same moment. Some simple balustrades appeared around the network’s opening, while more elaborate glass-covered structures and finished signage followed during 1900 and 1901. Guimard’s designs continued to be installed through 1913.
The year 1900 is therefore the canonical answer for when the Guimard Métro entrance series first appeared. It is not 1890, since Paris’s underground railway had not yet opened, and 1910 is too late. Many entrances were later removed, but surviving examples are protected as historic monuments.