The Opéra Garnier, also known as the Palais Garnier, or Paris Opera House, is one of the most characteristic buildings of the 9th arrondissement of Paris and of the cityscape of the French capital. Napoleon III ordered its construction by the architect Charles Garnier, who designed it in the Second Empire or Napoleon III style.

From its inauguration in 1875, the opera house was officially called the Académie Nationale de Musique-Theatre de l'Opéra. It retained its title until 1978, when it was renamed Théâtre National de l'Opéra de Paris. In 1989, the Opera Company moved its headquarters to the newly built Théâtre de la Bastille and its old home was renamed the Palais Garnier, where the National Academy of Music remains. Despite the official name change and the relocation of the Opera Company, the Palais Garnier is still popularly known as the Opéra de Garnier in Paris.

The Palais Garnier was designated as part of the transformations of Paris during the Second Empire, promoted by Emperor Napoleon III, who chose Baron Haussmann to oversee the works. In 1858 the Emperor authorised Haussmann to demolish the 12,000 m² required to build the second theatre for the renowned opera and ballet companies of Paris. The project was put out to tender in 1861, and was awarded to Charles Garnier (1825-1898). The foundation stone was laid in 1861, followed by the start of work in 1862. It is said that the Emperor's wife, Empress Eugénie de Montijo, asked Garnier during construction whether the building would be in the Greek or Roman style, to which he replied: "It's in the Napoleon III style, Madame!

The construction of the Opera had several setbacks. The work had to be interrupted when caves with underground water were found during the excavations, which had to be pumped out for eight months. It was also interrupted after the disaster of the Franco-Prussian war, the fall of the Second French Empire and the Paris Commune of 1870.

An incentive to finish this building appeared when the former Paris Opera House, known as the Theatre of the Royal Academy of Music (also known as the Theatre of the Imperial Academy of Music), was destroyed by a fire that lasted 27 hours on 29 October 1873. This theatre had been the home of Parisian opera and ballet since 1821, had performed the greatest masterpieces, and was the site of the heyday of Romantic ballet, alongside Her Majesty's Theatre in London. After 1874, Garnier and his team completed the theatre.

The Palais Garnier was officially inaugurated on 5 January 1875, with a ceremony that included a performance of the third act of Halévy's opera La Juive and excerpts from Meyerbeer's opera Les Huguenots. The ballet company presented a divertimento performed by ballet master Louis Mérante consisting of the famous scene from Joseph Mazilier's Le Jardin Animé, recreated from his ballet Le Corsaire.

In 1969 the theatre received new electrical installations and in 1978 part of the original Foyer de la Danse was converted into a new rehearsal space for the ballet company by architect Jean-Loup Roubert. In 1994 the restoration of the theatre began, which consisted of modernising the stage and electrical installations, while restoring and preserving the set and strengthening the structure of the building. The restoration was completed in 2006.

In 2011, a restaurant designed by French architect Odile Decq opened.