AHC: Germany annexes Alsace-Lorraine while avoiding war with France

With a POD anywhere from their surrender in WW1 (11th of November 1918) to OTL invasion of Poland (1st of September 1939) have Germany able to annex Alsace-Lorraine without getting embroiled in military conflict with France.
 
Maybe France somehow becomes embroiled in another violent revolution, this one communist in nature, and Germany reoccupies the Rhineland/Saarland when French troops are recalled by the government to fight the civil war. Later, the Germans occupy the city of Strasbourg to keep the peace when a riot breaks out, with the French military police in the area throwing down their arms and mutinying. Germany de facto administers Alsace-Lorraine until the situation settles, at which point it is incorporated into the Wiemar Republic.
 
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