Many are unaware that inside the Paris Opera built by architect Charles Garnier from 1862 to 1874 is hidden an instrument built by Cavaillé-Coll in 1874. Hidden ? Not really, but hidden from view since it is located on the Courtyard side at the level of the proscenium with pipes situated 12 meters high. It is an organ of 14 stops (18 with the borrowings) on two 56-note keyboards and a 30-note pedalboard fully closed in an expressive box. The inauguration took place on January 8, 1875 with the representation of the "Jewess" (La Juive) from Fromental Halévy. The organ is then used regularly according to the performance of works requiring its use. Alas, a first cry of alarm is launched in 1893 by Cavaillé-Coll himself who notices that his instrument has never been cleaned. The condition of the organ worsens, certain stops suffering from tone alterations ... On February 8, 1894 he considers the organ "in a state of disrepair"! In 1925, after a leak in the water column of the fire department, the organ was flooded and put out of service. It was at this time, during the repair by the house Cavaillé-Coll / Convers that some modifications were made, the most important being the installation of an electric fan, installed in a separate room located under the organ. This instrument was last used on March 23, 1959 to celebrate the centenary of the creation of Faust by Charles Gounod. The organist André Marchal plays at this occasion. He still played it occasionally in 1964. Since 1974, the organ has become unplayable and undergoes visible malfeasance, especially on the console. However, the original piping remains intact. This organ is kept in its original location desired by its manufacturer, which is unique in its genre. The organ has been classified as a historic monument since 1990. The issue of its restoration was raised since 2012. Source: Ministry of Culture built by Cavaillé-Coll in 1875 and is still in its original state, thus being a really exceptional witness of the work of Cavaillé- Coll in those years. It was last heard in 1968 and has been neglected since then and at present it is completely unplayable. Attemps to save this organ are ongoing.