Courseulles-sur-Mer is a commune in the Calvados department in the Basse-Normandie region in northwestern France.It is a popular tourist destination not only with locals but also with international visitors who come to tour the Normandy landing beaches. The population of the town can reach 15,000 people in the summer months owing to a large number of summer homes owned for the most part by Parisians.The town is split in two by the river Seulles.