Monaco is the sole municipality in Monaco, Monte Carlo was formerly a city, but since 1917 has been an area in the city of Monaco, not a city itself.
"The Principality is comprised on one municipality, Monaco" - Monaco government's website at: http://www.gouv.mc/devwww/wwwnew.nsf/1909!/x2Gb?OpenDocument&Count=10000&InfoChap=History%20%26%20Heritage&2Gb
If you read French, there's more info on this on the municipal council website here:
http://www.monaco-mairie.mc/01_monaco/hist/hist.php |