Résumé : This article examines a clandestine edition of Jean-François Marmontel’s Bélisaire produced in 1767 by the Liège printer Jean-François Bassompierre. Published shortly after the controversial reception of the work, which had been condemned by the Sorbonne, the edition forms part of the broader circulation of unauthorized and counterfeit Enlightenment texts in the eighteenth-century European book trade. Drawing on bibliographical evidence, typographical analysis, and archival sources, the study reconstructs the circumstances surrounding the production of this counterfeit edition. Particular attention is paid to the material features of the book and to the strategies employed by Bassompierre to reproduce and disseminate a work that had rapidly achieved international success. The article illustrates how material bibliography can help identify clandestine editions and clarify the practices of the eighteenth-century printing trade.