Alsace-Lorraine was the name given to the territory ceded by France to the newly-unified Germany under the 1871 Treaty of Frankfurt, which ended the Franco-Prussian War and restored to France after World War I by the 1919 Treaty of Versailles. Its legal name is Alsace-Moselle.

The transferred area corresponded to the French départements of Moselle, Bas-Rhin and Haut-Rhin. While the two latter corresponded to nearly all of the historical province of Alsace, most of the traditional Lorraine remained within France. French desire to recover the provinces was a major cause of the tragic alliance system that led to World War I.

Under the German Empire of 1871-1918, the territory constituted the autonimous Reichsland or Imperial Province of Elsass-Lothringen. The area had considerable autonomy under the federal German Empire, and had its own legislature and laws. These priveleges were partly lost when the area was restored to France.

It was again under German administration in 1940-45 during World War II.

To this day, the territory enjoys laws different from the rest of France on certain issues, see the statute of Alsace-Moselle.\n