[2][3] In his youth, he already composed a two-act opéra-comique, La Bannière du roi, with a libretto by Pierre Carmouche, which was first performed at Versailles in April 1835.
[2] His Roland à Ronceveaux, for which he wrote the libretto and the music, was staged in 1864[3] after Napoléon III transferred the management of the Opéra to the theatre.
[3] Mermet also composed a four-act opera, Jeanne d'Arc, to his own libretto based on a play by Jules Barbier,[3] which was the first premiere to be presented at the Palais Garnier (5 April 1876).
Gabrielle Krauss sang the title role, and Jean-Baptiste Faure was Charles VII, the ballet was choreographed by Louis Mérante, but the opera received only 15 performances, the last on 27 November.
[3] Hugh Macdonald, writing in The New Grove Dictionary of Opera, described his music as "direct, attractive, unadventurous, and noisy" and as modeled on Meyerbeer and Halévy.