[M2Ys4U]

>Don't know though how different court judgements are interpreted. I'd guess it would have to be an EU-court judgement for it to bind other courts.

If there is a contested interpretation of EU law then the lower courts of a member state MAY refer a question (or questions) to the CJEU to resolve the issue.

In the case of the highest courts (where there can be no appeal) they MUST make a referral to the CJEU.

These referrals also aren't "appeals" as such, either, but are designed to answer the questions in such a way that the member states' courts can resolve the case with an authoritative (and consistent) interpretation of EU law.