Portrait of the artist's son with his teacher, said to be the architect Jean-Baptiste de Courtonne the Younger, in a library

In the livret of the 1742 salon, the young pupil is identified as Lajoüe's son, while Marianne Roland-Michel (loc. cit.) has suggested that the seated gentleman may be the architect Jean-Baptiste de Courtonne the Younger (they were aged eleven and thirty respectively in 1742). Courtonne and Lajoüe must have known each other quite well, since both had been employed three years earlier by Bonnier de la Mosson, the architect responsible for designing Mosson's cabinets de curiosités and the painter for executing their décors.