"Champagne" is actually a brand, it just belongs to a region (of France) instead of a company.
> EU law and the laws of most countries reserve the term "Champagne" exclusively for wines that come from this region
> EU law and the laws of most countries reserve the term "Champagne" exclusively for wines that come from this region
We still (in Europe) call champagne anything that's a champagne in nature, regardless of origin, even if its maker can't say so on the label.
(The same way perhaps one would say "xerox" even if the machine is from another maker).