I think it is a breed? Although I'm not sure, when I googles it this came up-
The Harlequin is a colourful breed of rabbit originating from France. It is a breed based around the coloration and markings, rather than fur and body type.
It is both a breed and a color (and recognized in both the US and UK/AUS). The breed itself is pretty rare, I used to raise them. The harlequin breed only comes in the harlequin color but there are many other breeds that come in harlequin color as well.