There was no real fighting on the Western front for several months after the outbreak of war, this period dubbed as ‘The Phony War’. The actual fighting was at sea with the beginning of the Battle of the Atlantic. That changed in May 1940 with a German offensive that occupied Luxembourg, and moved in The Netherlands and Belgium. The Luftwaffe achieved air superiority in the West and massed German armor and infantry attacked France on May 13. The German forces swept through the French and British opposition and pushed them to Dunkirk. Paris fell on June 14th and France formally surrendered on June 25th. Germany now controlled most of the European continent.