It's supposed to be kind of sort of federal(ish) (federalish enough, in theory, to keep Catalonia and Euskadi happy enough that we won't want to leave). "States" are called autonomías (autonomies) and have their own government, laws, and institutions, though they still have to obey the Spanish government and most of its laws. It isn't really working.

The article is still wrong when it uses "feds", though, because the cops doing this are the mossos d'esquadra, the Catalan autonomic police, not the "federal(ish)" policía nacional (the Spanish police proper) or guardia civil (despite the name, the military Spanish police, a relic from Franco's dictatorship, like most of the country and its institutions).