FR: Rares mais marquantes ont ete les denonciations et les condamnations des crimes ou des vices des gouvernants. Le volume interroge les formes et les raisons de ces mises en cause, alors meme que les traditions antiques, medievales ou modernes etaient plutot accommodantes envers les abus de pouvoir. EN: Denunciations and convictions of rulers' crimes or vices are uncommon but striking. This volume investigates the forms and reasons for these accusations, even though antique, medieval or modern tradition has tended to be quite accommodating towards the abuse of power.