Abstract: The Difficultés sur la religion that Challe would seem to have addressed to Father Malebranche is an indictment (written between 1710 and 1714) of the Church and theologians, especially Catholic ones. This condemnation of imposture is divided into three parts: the lived experience of a victim of imposture, the tactics used and the damages incurred by this victim, and the obligation to resist. The upshot is that, out of all the “difficultés” with religion, imposture is, for Challe, one of the thorniest if not the most indestructible.