Fort Cépérou is the small hilltop fort that marks the very foundation of Cayenne — French settlers, led by Charles Poncet de Brétigny, built a wooden stockade here in 1643 on a hill granted by the Galibi chief Cépérou. The current stone walls date mostly from the 17th and 18th centuries and have served as a fort, a barracks, and a prison in turn.
The ruins are modest, but the view over the city, the harbour and the Cayenne River is the best in town. Take the steps up from Rue Madame Payé. Visit during the day; the path is not safe after dark.