The calculated distance (air line) between Reims and Champigny-sur-Marne is approximately 76 miles respectively 123 kilometers.
By car or train, the actual journey to Champigny-sur-Marne is certainly longer, as only the direct route (as the crow flies) between Reims and Champigny-sur-Marne has been calculated here.
Air line (approximately)
123 kilometers
66 nautical miles