The calculated distance (air line) between Cergy-Pontoise and Vitry-sur-Seine is approximately 23 miles respectively 37 kilometers.
By car or train, the actual journey to Vitry-sur-Seine is certainly longer, as only the direct route (as the crow flies) between Cergy-Pontoise and Vitry-sur-Seine has been calculated here.
Air line (approximately)
37 kilometers
20 nautical miles