This is one of a remarkable set of pictorial propaganda maps produced by a British officer in a German prisoner of war camp, approved and made available by German authorities, and published in Britain in 1941 with government consent. See Notes and other information for ID #2346.01.
Hunt, Leslie C. 1941. The Prisoners' Progress. An Illustrated Diary of the March Into Captivity of the Last of the British Army in France - June 1940. London: Hutchinson and Co.