Maillart came from an artistic family, his two brothers already accomplished artists in the fields of graphics and architecture. A voyage to Italy as well as studies of ancient scuptures revealed Maillart's passion of painting Roman subjects. He debuted at the Salon in 1870. He executed a number of murals over the staircases of the Château de Chantilly amongst others. His portraits and small genre scenes are often allegorical and exemplify his confident and vivid style.