500 000 000 Mark

Duisburg's 500-million-mark note dates from the peak of the German hyperinflation — autumn 1923, when municipal and commercial issuers across the Rhineland were printing emergency currency (Notgeld) because Reichsbank denominations were obsolete almost the moment they were issued. Duisburg's position in the occupied Ruhr, under Franco-Belgian control since January 1923, added a particular wrinkle: the occupation authorities restricted normal economic activity, accelerating the local collapse and forcing civic bodies to self-issue at a pace that bordered on absurd.

Locally printed series like this one typically show rougher production values than centrally issued notes — worth checking the serial numbering for inconsistencies, as overprinting and hand-stamping were common shortcuts when denominations were revised faster than new plates could be made.