It's pretty clear from the context and implications that when European legislators wrote "public authority" into the General Data Protection Regulation they didn't mean the same as the drafters of the UK's Freedom of Information Acts. "Public authority" isn't defined in the Regulation and I've not been able to find it in any other European law, so I'm grateful to David Erdos for pointing out the case where the concept and reason for it, if not the actual phrase, were discussed.