Plattemontagne was active in the studio of Philippe de Champaigne alongside the master's nephew Jean-Baptiste de Champaigne, where they both absorbed the elder Champaigne's restrained style. He later studied with Le Brun and became a professor at the Royal Academy. Plattemontagne is little known as a painter and it is only recently that his oeuvre has been reconstructed, yielding a corpus of seventeen paintings, and eighty drawings and prints. Drawings by the artist are robustly executed and document his careful preparation for projects, following the academic model. This study for a seated female figure holding a martyr's palm in her left hand and resting her right hand on the head of a lamb depicts St. Agnes, though no painting by the artist including the saint is known. Plattemontagne repeated the study of the figure's left hand at upper right, refining and clarifying the position of the fingers. He was a skilled portraitist and a number of the artist's extant drawings study a figure's torso and drapery, with close attention to the hands.