At the end of WW1, in November 1918, a red flag was floating on top of the cathedral. Strasbourg was declared a socialist republic, for about 10 days, until the french army "liberated" the town.
Last night, some partisans of the independence from France floated the "Rot Wiss" ,red and white alsatian flag on top of the same cathedral. It was removed by the police at 10.30 AM.
Below, the press photo;