Those are made by any shop that prints on plastic of metal. It's not allowed of course, but who cares. Especially in a country where they let you drive the first 3 months with a piece of white paper with a dealer license plate. In most countries the license plate works to be able to track you down, here it's more a proof you paid the import tax.
For example, in Turkey they have 2 options, US sized or EU sized license plate, so you can choose which one looks better for your car. Here poor Mini Cooper owners have to fabricate the plate (I think the original plate is in the trunk).