This is a very ordinary commercial vehicle plate. Until 2008 ALL commercial vehicles had this colour. Since 2009, you have been able to register your commercial vehicle in a way that allows you to use it privately. These half private/half commercial have a yellow background beneath the letters and a white background beneath the numbers. But this is a very, very common Danish plate. BTW i'm a Dane! ;-)

The Greeks have their own alphabet, from wich the cyrillic one is inspired from, but they're nowhere near the same alphabet...