After studying the trumpet at the conservatory in Reims and the Conservatoire de Paris, he worked as a teacher for this instrument.
The combination of his experience in trumpet playing and his fondness for the repertoire of early music then led him to his interest in the cornett.
To learn the instrument he took courses with Jean-Pierre Canihac and Bruce Dickey at the Schola Cantorum Basiliensis.
[2] Dongois played for recordings with orchestras such as Hespèrion XXI and Concerto Palatino and with conductors such as Ton Koopman, Andrew Parrott, Joshua Rifkin, René Jacobs and others.
Until 1993, he was a member of the ensemble La Fenice, with which he won first prizes at the music competitions for orchestras in Bruges (1990) and Malmö (1992).