This article explores the relationship between law and violence against slaves in nineteenth-century French Guiana. Drawing on unpublished sources from the colonial archives, Spieler examines the linked problems of slave abuse and slave flight to understand the evolving character of the French imperial state in the aftermath of the Napoleonic Wars. In the early nineteenth century, after the abolition of the slave trade, imperial administrators in Guiana contested the proprietary privileges of masters and lay claim to the right to punish slaves. During the 1820s and 1830s, slave testimony—especially the testimony of abused slaves (inside and outside the courtroom)—became unexpectedly central to this dispute between masters and administrators about the source of legitimate violence and the meaning of imperial sovereignty.