The Italian name for München/Munich is Monaco (literally "monk"), which makes a lot of sense now :)
The city state of Monaco is also called Monaco in Italian. Both the English and the Italian names are derived from the Greek word Monoikos, meaning "single house".
The German city of München is called Monaco in Italian and Monacum/Monachium in Latin. The Italian name derives from the Latin name, which in turn is derives from the Latin word for monk.
To avoid confusion, the German city is more commonly referred to as "Monaco di Baviera" (Monaco of Bavaria) to better differentiate it from the microstate.