Alsace:

During the First World War, to avoid ground fights between brothers, many Alsatians served as sailors in the Kaiserliche Marine and took part in the Naval mutinies that led to the abdication of the Kaiser in November 1918, which left Alsace-Lorraine without a nominal head of state. The sailors returned home and tried to found a republic. While Jacques Peirotes, at this time deputy at the Landrat Elsass-Lothringen and just elected mayor of Strasbourg, proclaimed the forfeiture of the German Empire and the advent of the French Republic, a self-proclaimed government of Alsace-Lorraine declared independence as the "Republic of Alsace-Lorraine". French troops entered Alsace less than two weeks later to quash the worker strikes and remove the newly established Soviets and revolutionaries from power. At the arrival of the French soldiers, many Alsatians and local Prussian/German administrators and bureaucrats cheered the re-establishment of order (which can be seen and is described in detail in the reference video below). Although U.S. President Woodrow Wilson had insisted that the région was self-ruling by legal status, as its constitution had stated it was bound to the sole authority of the Kaiser and not to the German state, France tolerated no plebiscite, as granted by the League of Nations to some eastern German territories at this time, because Alsatians were considered by the French public as fellow Frenchmen liberated from German rule. Germany ceded the region to France under the Treaty of Versailles.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". What treaty gave Alsace to Germany?
unanswerable