I find the event was in 1988. It wasn't a demonstration per se but the occupation of a special place: a triangular area belonging to East Germany but cut off by the Berlin Wall, which was handed over to West Germany in a territorial exchange on 1 July 1988. The occupation started after a street protest of the non-aligned anarchistic radical Left (who call themselves Autonomen = "the Autonomous" in Germany) on 26 May 1988, with the aim to prevent a highway construction. When West German police stormed the area on day they gained authority over the area, 182 (Wikipedia) or 220 (linked article) fled towards the Wall.

I found photos here.

_{*Lunatic*, n.
One whose delusions are out of fashion.}