The careers of the father and son as merchants of paintings expanded from their roles as printmakers, editors and printsellers.
When Charles Joullain married Catherine Louise Leclerc, the daughter of Sébastien Leclerc (1676-1763) in around 1756,[2] his father transferred to him the portion of his business that dealt with frames[3] and he supplied his father with frames for his auctioneer's rooms at Quai de la Mégisserie à la Ville de Rome, Paris.
[4] After his father's death in 1778, he continued to run the family business and became one of the most prominent art dealers in Paris in the second half of the 18th-century.
[9] Francois-Charles Joullain was the author of three works which serve the historian of the art market as a guide to auction house practices in the 18th century: his Répertoire de tableaux, dessins et estampes, ouvrage utile aux amateurs, 1783, his Variation de prix concernant les tableaux, 1786, and above all his Reflexions sur la peinture et la gravure, accompagnées d'une courte dissertation sur le commerce de la curiosité et les ventes en général, Metz, 1786.
[12] Joullain's contribution was to compile the first index that documented provenance and the prices paintings had fetched at auctions.