Types C and E, 230 V, 50 Hz – those are the basics for electricity in Monaco. A converter can stay at home; Monaco supplies 230 V.
You will find identical sockets in France, Czechia, Poland and Slovakia. Nearby but different: Cyprus, the United Kingdom and the Isle of Man – an adapter for Monaco will not fit there. In Europe, 6 of 50 recorded destinations use exactly this combination.
Protective earth
Grounded and ungrounded sockets may occur
Monaco has sockets with a protective earth (Type E) and without (Type C). A plug that fits mechanically does not guarantee earthing.