Barthélemy graduated his conducting degree summa cum laude in 2016 and started conducting orchestras in Rouen and Paris. He also graduated in analysis and musical theory at the Rouen Conservatory. After having started music at an early age with piano and trombone, these degrees marked a first accomplishment in his career.
His first experience as conductor was the Opus 76 orchestra which with he conducts many concerts in France notably in the Rouen opera in 2017. This orchestra continues growing and has just played at the Berlin Philharmony in February, 2020, in a collaboration with the OBM orchestra of Berlin. Concerts are also programmed in Rennes, Paris, Lille and London in the next few years.
Since 2017, he is assistant to Jean-Philippe Sarcos at the Palais Royal orchestra. He conducts rehearsal with choir and orchestra. He also conducts the Paris music Academy in which he conducts many concerts. Each December in the greatest churches of Paris for sacred music program, and in the winter circus for a profane music concert, often based on operetta music. The success of the Paris music Academy is still ongoing and the choir and the orchestra combined gather more than two hundred people.
Since 2018 he his assistant to Maestro Luciano Acocella in lyrical productions in various opera houses such as Massy, Paris, Orange and Rouen. He also assisted the Maestro at a TV production in the antic theatre of Orange.
Since 2019, he is Musical Director of the Orchestre Romantique de Paris.
He additionally conducted the Orchestre National de Normandie, the Orquesta da Costa Atlantica in Portugal, the OBM of Berlin and the Makris Symphony Orchestra in Belgrade.