Plessier was born at 11pm on 19 May 1856 at Provins, Seine-et-Marne to Louis Francois Plessier, a lawyer, and his wife Victoire Toureau [REF].
Plessier was promoted to lieutenant on 13 October 1882 in the 121st Line Infantry Regiment and transferred to the 3rd Marine Infantry Regiment on 5 July 1884 [REF].