After doing some digging, it looks as if Supreme Spain is an official brand, not connected in any way with the New York City-born Supreme. You'll quickly notice, however, that Supreme Spain has taken significant liberties with its product design, making heavy use of the famed box logo.
The Supreme Spain website also houses a number of "similar" items to that of the OG brand, including box logo tees and hoodies, bags, headwear, and more. Follow here to take a look.
In related news, a streetwear company in China recently hired an actor to pose as the “President” of Supreme.