[suum cuique]

Originally Posted by Don M

It's from the Schutzpolizei of the Düsseldorf administrative district --- the command at either Krefeld-Uerdingen or München-Gladbach (http://www.historywritinsteel.com/New_Insights.html).

The name of the city "München Gladbach" was officially changed to "Mönchengladbach" in 1960 to avoid a confusion with the name of the city of "München" (Munich) in Bavaria.