The Corps of Carabinieri has got a very antique origin and was founded in the far 1814. Its tasks are very similar to those of police, even if the differences between them are a lot. The Carabinieri almost always used the same license plates of the Italian Army, those with Servizio Militare (SM) at the beginning and then those of Regio esercito and at last those with EI. I said "almost" because there are two exceptions.
1945-1949: this is what I read on the web site Le
autovetture dei Carabinieri (I've just translated it from Italian):
"In the short time between 1945 and 1949 a new CC.RR plate was issued for all the vehicles of the Carabinieri with a civil plate: this was very rare (used on just 4.000 vehicles in total) and not right for that time. In fact CC.RR stands for Carabinieri Reali (Royal Carabinieri), but after the Second World War Italy was not a monarchy any more, but a repubblic. In those same years the other vehicles of the Carabinieri (known as military) kept using the plates of the Italian Army, with the letters E.I. The CC.RR. plate was abandoned in 1950 (for unknown reasons) and in March 1951 the General Command of the Corps of Carabinieri made a wide research about the possibility of a CARABINIERI plate and sent it to the Ministry of the Interior and of the Defence. In this document you can read: "...the need of image to let the citizen match the vehicle with the corps... a CARABINIERI plate could be used as it happens with the vehicles of the POLIZIA...". Anyway this document didn't have any effect."
The picture number 1 shows one of these plates.
Alessandro Libanore found the plate shown in the second image: the letters CC stand for Carabinieri and it seems that this plate was used between 1945 and 1949. This is obviously against what written above about the letters CC.RR.: I'll try to solve this puzzling mistery as soon as possible.
Picture 1: 1945-1949
Picture 2: 1945-1949
2000-Today: in 2000 the Corps of Carabinieri became the fourth armed force of Italy and a new plate was introduced. They are identical to the plates used by the Italian Army except for the red letters CC in place of EI. Indeed, all the CC plates issued before June 2001, both for car and for motorcycle, were made adding a little metallic square with the red letters CC over a regular plate of the Italian Army (both those with the format EI 000 AA and those with EI AA 000), as it's clear in the pictures number 4, 5, 6 and 7 below: this was probably due to the fact that the new plates were not ready yet and anyway they were compatible with the unified numbering system of the armed forces.
Picture 3: 2000-Today: Rear plate, 2 lines
Pictures 4, 5, 6: 2000-2001: Old and new format, with added CC tag
Picture 7: 2000-Today: Trailer
Picture 8: 2000-Today: Motorcycle
Picture 9: 2000-Today: Working vehicle(macchina operatrice)
In this web site you can also find two more pictures of special plates of Carabinieri used in the Italian colony of Libya.
Many thanks to Adolfo Arena for the picture number 3, to Marcello Taverna for the pictures number 4 and 6, to Roberto Grando for the picture number 7 and to Zirrio for the picture number 8.