The calculated distance (air line) between Duisburg and Saint-Amand-les-Eaux is approximately 160 miles respectively 258 kilometers.
By car or train, the actual journey to Saint-Amand-les-Eaux is certainly longer, as only the direct route (as the crow flies) between Duisburg and Saint-Amand-les-Eaux has been calculated here.
Air line (approximately)
258 kilometers
139 nautical miles