Yes and no, the EU isn't a nation, it doesn't have full control over its members, thus its capacity to make laws is restricted in certain domain. The scope of the EU is written in the treaties. It's fairly complex and there are grey areas, even as a EU citizen I don't have a perfect understanding of everything.

Exxon is going to be brutally introduced to the fact that the EU is in reality fairly free when it comes to that subject and very determined.