Named BBC Music Magazine's 2018 Revelation of the Year, Julien began learning the piano at the age of 5 and performed for the first time at the Salle Cortot (Paris) at the age of 7. He was trained by Erik Berchot at the Conservatoire National de Région de Marseille and Rena Shereshevskaya at the École Normale de Musique de Paris Alfred Cortot. He was supported by the Zaleski Foundation, the Assophie Association and the Fondation Safran during his training.

He was spotted in January 2013 by Maria João Pires during an advanced course at the Cité de la Musique (Paris). She then invited him for an artistic residency at the Chapelle Musicale Reine Elisabeth in Belgium. She will present him in numerous concerts throughout the world, including the Warsaw Philharmonic for the prestigious Chopin Festival, the Florence Opera in the Great Artists series, the Sheldonian Theatre (Oxford), the Alfredo Kraus Auditorium (Las Palmas) and the Philharmonie de Paris.

He has also given numerous recitals around the world, including Wigmore Hall (London), New York Town Hall, the Festival Classique au Vert, Piano aux Jacobins, the Chopin Festival in Nohant and the Tippet Rise Art Center in the USA (Montana), the Cambridge Music Festival, the Chopin Society (London) and the NCPA (Beijing), replacing at short notice the famous pianists Fazil Say and Nelson Goerner.

Highlights of the 2022-2023 season include the release by Rubicon Classics in May 2023 of his third solo album "Here" dedicated to his compositions recorded at the Tippet Rise Art Center prior to the pandemic, a tour of the United States, and the release of a triple album by Deutsche Grammophon dedicated to Chopin with cellist Camille Thomas.

Julien is also a regular chamber music partner of cellists Lidy Blijdorp, Camille Thomas and violinist Rosanne Philippens, co-organizing with pianist Julien Libeer the chamber music festival "Pause Festival" in La Donaira, Andalusia.

Julien also works to bring music and the arts to unusual places, to organize workshops to introduce classical music, and educational projects for children in difficulty. He has contributed to the development of the children's choir Equinoxe created by Maria João Pires and is involved as a conductor in the children's choir Singing Molenbeek which works in the schools of Molenbeek in Brussels.

Music is often identified as entertainment, but it is also a tool that Julien proposes as a vector of care and therapy. He initiates with the Doctor in psychology of emotions Ilios Kotsou regular sessions of Musical Breathing, which will soon be broadcasted via an open source mobile application.

His first album published in 2017 is dedicated to the repertoire of Frederic Chopin with the 24 Preludes Op. 28 and the Sonata No. 2 Op.35. The recording was unanimously praised by the international press, the BBC Music Magazine said that it is a "Chopin bewitching", giving it 5 stars and presenting it as its best instrumental album of the month.

His second album, consisting of works by Ravel and Mompou, was released in 2018 and was received with equal enthusiasm by the international press: Gramophone magazine editor Patrick Rucker wrote "I implore you not to miss the opportunity to hear this singular talent."

In addition to traditional concert halls, Julien has created in his studio the “Jardin Musical," a creative ecosystem reflecting the principles of permaculture by providing a space to produce live performances, recordings and residencies.