That's not how things work. Under german law, if you provide a service that is targeted at german customers you're bound by german (hence EU) rules for that tra

That's not how things work. Under german law, if you provide a service that is targeted at german customers you're bound by german (hence EU) rules for that transaction, no matter where your company is located [1]. Enforcement may still be a problem, but since Facebook obviously needs to display ads that are locally relevant they need to have business interactions with EU company and it would be possible to make that at least harder, if not impossible. The EU doesn't need to block Facebook to punish it. Facebook may withdraw from the EU market as a result, but that's voluntary from facebooks side. [1] having a german localization is a strong indicator in that case.