Shortly after World War 1, Germany was forced to relinquish control over Alsace back to France. However, During the Beginning on the 20's, The still majority German population grew unhappy of French Rule and sought to secede as a united Alsatian nation-state. So on the 17th of July, 1921. Much of Alsace revolted against France to fulfill their destiny as a people. With France still repairing from the war; They didn't offer much resistance to the Alsatian Revolt and figured it was better to let them go. After Alsatian sovereignty was secured, The major political figures met in the Council of Selestat to set terms for the Alsatian Constitution. However, This eventually failed as the cities of Strasbourg, Mulhouse and Colmar kept arguing on their city being the capital, This dispute proved to tear Alsace apart as the three chose to split into their own countries and part ways in the 8th of March, 1922. In the October of 1938, The Three would be forced to be annexed by Hitler's Third Reich like Austria and Czechia. After World War 2, Alsace was again given to France while Germany was occupied by the allied powers. Again, Alsace didn't like France and revolted in 1953. This time, France actually decided to counter their revolt before being forced to back down by the UN. The Alsatian revolutionaries would meet in Munster and, Again, Would fail to choose a capital for Alsace so they split once more, On December 28th of 1955. Strasbourg and Mulhouse returned with Duke Albrecht I Verkampfen returning to power. 5 days later in the 2nd of January, 1956 Colmar would be re-established. In 1963, The Ribeauville Council would be formed as an economic alliance between the three states to strengthen relations. In 1971 Strasbourg, Mulhouse and Colmar all adopted a single unitary currency, The Serrad. this is also when they all join NATO. Today, All three countries are highly developed and have great relations with each other, They also consistenly rank in the top 20 for quality of life and freedom.
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Anyways this is a scenario that i made up for fun, open to thoughts and suggestions.
I love your style of map!
I doubt the plausibility of this scenario, though.
France has just won the war to end all wars, and they've won. Their reward: a highly contested piece of land which they lost just a few decades prior. Then, two years later, the German population they've just fought many of the largest battles ever to secure revolts again, and they think, "you know, maybe they deserve independence anyway - a chance to govern themselves as a people". They botch this chance, disintegrating over a petty capital dispute, and the French continue to stay away inexplicably.