From the German Wikipedia page [1]

The City Archives - Bochum Center for City History is located on the Wittener Straße of Bochum (Wikipedia page [2]), Germany. It takes over the functions of municipal archive and the historical museum of Bochum.

The archives "comprise archives, documents and protocols, maps and plans, posters and bills, newspapers and printed material, image carriers and phonograms, films, collections on different topics and various additional documents from more than 800 years of Bochum history."

An external site is located in the Gertrudis Center in Wattenscheid. The old premises on Kronenstraße serve as an archives of 835 files as one of 19 archives for the existence of the Cologne City Archives.

The website, in German, is [3].