In 1863, the Saint-Sernin Works Committee decided to install a choir organ, inspired by the success of this type of instrument in the churches of Paris. The Toulouse organ builders Puget were commissioned to build what was destined to be the first choir organ in Toulouse. The instrument was financed by private donations. At that time the organ possessed four full stops and a 16-foot bourdon half-stop. The entire instrument took up barely more space than a harmonium and confirmed the design skill of the organ builders. It was inaugurated in November 1863. In 1874, the Works Committee decided to replace the instrument with a larger model. The case was designed by Viollet-le-Duc to sit perfectly amongst the stalls. The construction was again entrusted to the Maison Théodore Puget et Fils. The organ was inaugurated on Thursday the 27th of January 1876. During the same period, the organ builders were negotiating a contract with the Works Committee of Notre-Dame du Taur. The successful installation of the modest Saint-Sernin instrument no doubt strengthened their hand. The Pugets continued to maintain the instrument. In 1932, the organ seemed to be declining and the Works Committee called upon Maurice Puget for a thorough overhaul. On this occasion, he replaced the clairon of the first manual with a plein jeu. The renovated organ was inaugurated in 1934 by François Vidal, the titular organist of the choir organ. More recently, the choir organ was restored again at the same time as the grand-orgue, a new plein jeu being installed. The organ is now maintained by Patrice Bellet.