Deplus studied clarinet at the Conservatoire National Supérieur de Musique de Paris and received Premiers Prix in clarinet and chamber music. He was a professor of clarinet at the Conservatoire National Supérieur de Musique de Paris, and is now retired. He taught many French orchestral clarinetists. He was also one of the clarinetists who collaborated with Buffet Crampon on the creation of the Tosca and Festival clarinets. Together with Pierre Boulez, Deplus cofounded the "Concerts du Domaine Musical". He was a soloist in the Paris Opera. Deplus received the Lifetime Achievement Award from the International Clarinet Association (for "Outstanding Performance, Teaching, Research, and Service to the Clarinet).