From Paris, A13 slices its way to Rouen in 1½ hours (toll EUR 5.20) before forking to Caen (an additional hr, toll EUR 7.50) or Le Havre (45 mins on A131). N13 continues from Caen to Bayeux in another two hours. At Caen, the A84 forks off southwest toward Mont-St-Michel and Rennes. From Paris, scenic D915 will take you to Dieppe in about three hours. The Pont de Normandie, between Le Havre and Honfleur, effectively unites Upper and Lower Normandy.