I had the same question when I started teaching online a few years ago (but I am American, so it solves the problem).

My suggestion: On the Private Tutors board of this site, you will see a tab called "Students/Tutors Portals" http://www.eslteachersboard.com/cgi-bin/tutors/index.pl?&filter=typeid&typeid=9#bbs Some portals are based in Europe, China, Korea, US, etc. If you chose the ones that are based in Europe - we can assume that they cater to European students - you can ask them 1 or 2 simple questions like "If I post my resume on your portal, and I get students from Europe, do I have to register for VAT with the EU?" One of them might answer.

The alternative is asking the question to the EU (I know, I know, you will need some good luck and a lot of patience). You can do this anonymously.

Whatever you learn, if you have time to post some info here, it would help other online tutors as I am sure everybody is confronted with the same question at some point.