There were a number of significant delays however, first there were issues such as the Paris Commune, and the Franco Prussian War and then, there was a problem with the location. The ground was marshy and full of underground water.

For eight months, the site had to undergo constant pumping before the base could be put down and it was said to have formed an underground reservoir. This reservoir became the idea behind the setting of "The Phantom of the Opera"

On January 15, 1875 marked the opening of the Palais Granier (Paris Opera House). There was a performance of La Juive with Fromental Halevy and excerpts of Les Hugentos with Gaicomo Meyrebeer.

The editor John Norwich of Great Architecture of the World reports that a contemporary critic thought the Opera House looked like "an overloaded sideboard" The place is ornate and decorated with marble friezes of various colors.

The interior is filled with gold leaf and velvet. There are cherubs and nymphs everywhere. The chandelier is over six tons in weight. The ceiling itself was painted by Marc Chagall in 1964. The Opera House is 11000 square meters (11844 square feet) with a platform that can fit more than 400 artists and there are over 2000 seats for the audience.

The Opera House is now thought to be a masterpiece because Garnier had made wonderful use of the difficult and cramp site. The carriage ramps, the steps, the foyers and staircases were both planned and sectioned with skill and confidence.

Garnier was accused of being overly ornate, just like Napoleon and Haussman were criticized of having old and imperialist ideas but the critics forget to keep in mind that cities need their grand monuments and without Napoleon, Garnier, and Haussman, Paris could not have been thought of as one of the most beautiful cities in the world.