Canada

Some of them are flying the Confederate flag in Alberta!

Historically Europe (and the British Empire) sided with the confederacy because they saw a united USA as a potential industrial rival, whereas the south was more of a resource colony. Interestingly there was a major class divide in Europe where the working classes were anti-slavery and therefore anti-confederate wheras the upper classes saw the confederate cause being in their interest. There's a book about this called A Cause for All Nations by Don Doyle.

My understanding is that nowadays the confederate flag is used by people outside the USA who are on the fascist end of the spectrum for whom Nazi or fascist symbols are too extreme (or just illegal) in their countries.