With "Le Trompette de Chamboran" Deffès returned to the opera stage in 1877. His symphonic overture "Un Triomphe à Rome" was performed at the 1878 World Exhibition. A new mass by Deffès was performed at the Saint-Etienne Cathedral of Toulouse in 1879. Here he succeeded Paul Mériel as director of the Conservatoire de Toulouse in 1883. He held the position until his death, his successor was Bernard Crocé-Spinelli.