There's information in the Sur in English link I posted and also in Sede link that Spanish Lad posted above.
The Spanish sticker is not valid outside of Spain, but some foreign stickers are acceptable here:
Can I drive with my badge from another country in restricted areas within Spain?
Yes. You can check the equivalence between the classifications of the different countries . In this way you will be able to know the equivalent Spanish emblem of your vehicle, knowing what traffic restrictions may affect you, and being able to drive on our roads with the emblem of your country.
https://sede.dgt.gob.es/es/vehiculos/di ... l-ue.shtml