The calculated distance (air line) between Cergy-Pontoise and Levallois-Perret is approximately 14 miles respectively 22 kilometers.
By car or train, the actual journey to Levallois-Perret is certainly longer, as only the direct route (as the crow flies) between Cergy-Pontoise and Levallois-Perret has been calculated here.
Air line (approximately)
22 kilometers
12 nautical miles