Desgraviers was born at Chartres, Eure-et-Loir. His father served as a legal officer, and Marceau received an education for a legal career, but at the age of sixteen he enlisted in the regiment of Savoy-Carignan. Whilst on furlough in Paris, Marceau joined in the storming of the Bastille on 14 July 1789 – after that event he took his discharge from the regular army and returned to Chartres, but the opposition of his family soon compelled him to seek new military employment. He became a drill instructor and later a Captain in the Eure-et-Loir départemental regiment of the National Guard.