Châtillon-sur-Seine (shätēyôNˈ-sür-sĕn) [key], town (1993 est. pop. 7,451), Côte d'Or dept., N central France, in Burgundy, on the Seine River. It was a residence of the early dukes of Burgundy and has a 10th-century church. The town was the site of unsuccessful peace negotiations (1814) between Napoleon I and his opponents.