Why was the Rhineland separate from Germany and who controlled it?

In 1920, under massive French pressure, the Saar was separated from the Rhine Province and administered by the League of Nations until a plebiscite in 1935, when the region was returned to Germany. At the same time, in 1920, the districts of Eupen and Malmedy were transferred to Belgium (see German-Speaking Community of Belgium).

Shortly after, France completely occupied the Rhineland, strictly controlling all important industrial areas. The Germans responded with passive resistance and hyperinflation; the French gained very little of the reparations they wanted. French troops did not leave the Rhineland until 1925.