Hector Guimard in the context of "Salon d'Automne"

Eugène Emmanuel Viollet-le-Duc (French: [øʒɛn vjɔlɛ lə dyk]; 27 January 1814 – 17 September 1879) was a French architect and author, famous for his restoration of the most prominent medieval landmarks in France. His major restoration projects included Notre-Dame de Paris, the Basilica of Saint Denis, Mont Saint-Michel, Sainte-Chapelle, the medieval walls of the city of Carcassonne, and Château de Roquetaillade in the Bordeaux region.

His writings on decoration and on the relationship between form and function in architecture had a fundamental influence on a whole new generation of architects, including all the major Art Nouveau artists: Antoni Gaudí, Victor Horta, Hector Guimard, Henry van de Velde, Henri Sauvage and the École de Nancy, Paul Hankar, Otto Wagner, Eugène Grasset, Émile Gallé, and Hendrik Petrus Berlage. He also influenced the first modern architects, Frank Lloyd Wright, Mies van der Rohe, Auguste Perret, Louis Sullivan, and Le Corbusier, who considered Viollet-le-Duc as the father of modern architecture. English architect William Burges claimed that "We all cribbed on Viollet-le-Duc even though no one could read French".

Between 1900 and 1913, Hector Guimard was responsible for the first generation of entrances to the underground stations of the Paris Métro. His Art Nouveau designs in cast iron and glass dating mostly to 1900, and the associated lettering that he also designed, created what became known as the Métro style (style Métro) and popularized Art Nouveau. However, arbiters of style were scandalized and the public was also less enamored of his more elaborate entrances. In 1904 his design for the Opéra station at Place de l'Opéra was rejected and his association with the Métro ended; many of his station entrances have been demolished, including all three of the pavilion type (at Bastille and on Avenue de Wagram at Étoile). Those that remain are now all protected historical monuments, one has been reconstituted, and some originals and replicas also survive outside France.

Victor Pierre Horta (French: [viktɔʁ ɔʁta]; Victor, Baron Horta after 1932; 6 January 1861 – 8 September 1947) was a Belgian architect and designer, and one of the founders of the Art Nouveau movement. He was a fervent admirer of the French architectural theorist Eugène Viollet-le-Duc and his Hôtel Tassel in Brussels (1892–93), often considered the first Art Nouveau house, is based on the work of Viollet-le-Duc. The curving stylized vegetal forms that Horta used in turn influenced many others, including the French architect Hector Guimard, who used it in the first Art Nouveau apartment building he designed in Paris and in the entrances he designed for the Paris Metro. He is also considered a precursor of modern architecture for his open floor plans and his innovative use of iron, steel and glass.

Horta's later work moved away from Art Nouveau, and became more geometric and formal, with classical touches, such as columns. He made a highly original use of steel frames and skylights to bring light into the structures, open floor plans, and finely-designed decorative details. His later major works included the Maison du Peuple/Volkshuis (1895–1899), Brussels' Centre for Fine Arts (1923–1929) and Brussels-Central railway station (1913–1952). In 1932, King Albert I conferred on Horta the title of Baron for his services to the field of architecture.

Opéra (French: [ɔpeʁa] ) is a station on Lines 3, 7 and 8 of the Paris Métro. It is named after the nearby Opéra Garnier. Located at the end of the Avenue de l'Opéra, it serves the district of Boulevard Haussmann. Its main entrances are located on the Place de l'Opéra, built in a marble design (instead of the characteristic iron metro entrances of Hector Guimard), to not spoil the view of the opera house.

The station is connected by an underground passage to Auber on RER A. From Auber, additional stations and lines can be reached via a sequence of underground passages, namely Havre–Caumartin for Line 3 and Line 9, and Haussmann–Saint-Lazare for RER E, the latter being connected to Saint-Lazare for Line 3, Line 12, Line 13 and Line 14, and the latter in turn being connected to Saint-Augustin for Line 9.

The Castel Béranger is a residential building with thirty-six apartments located at 14 rue de la Fontaine in the 16th arrondissement of Paris. It was designed by the architect Hector Guimard, and built between 1895 and 1898. It was the first residence in Paris built in the style known as Art Nouveau.