The date is questionable, but the fact that Jullien was appointed organist of the cathedral while still very young is indisputable. He occupied this position until his death in Chartres in 1703. He was succeeded at the cathedral by his eldest son, Jean-François Jullien.
While the exact year of appointment is unclear, it's certain that Jullien was appointed organist of the cathedral while still young. He held this position until his death in Chartres in 1703. His eldest son, Jean-François Jullien, took over the role after his father's passing.