Calais which lies in the department of Pas de Calais is a part of the region of Nord Pas de Calais which is included in Northern France. The area of Pas de Calais was primarily dependent on coal since long times. But the disastrous event of World War II had made huge impact on the department's economy making it more diverse.
Calais is a coastal town and its closeness to England led it to its development into a major port since many centuries. France and England have been bonded together by the English Channel as the major ferry ports of Calais in France and the town of Dover in South East England are utilized for trade. The French end of the English Channel lies at Coquelles which is just 4 miles away from Calais.
The foundation of the town's economy has and will always be its port, but apart from that it also produces indigenous products such lace, chemicals and paper. It is directly linked to Paris via railway lines.
The taxes imposed by both UK and French government are vastly different with alcoholic drinks cheaper in Calais. It's nearness to England; make it a frequent tourist centre for day trippers who buy alcohol on a huge scale. But as the countries follow EU custom rules, no restrictions can be imposed as long as the drinks bought are for personal use.
Calais is connected directly to Europe and England via the Eurostar line with the international station of Gare de Calais-Fréthun being the first stop in Europe. The other railway station is Gare de Calais-Ville.