Hi OP, hope you don’t mind - just reposting my answer to this question from the other thread, in case anyone on here has any thoughts. As I said, I’m not sure if it’s right, but this is how I would be thinking about the question.
Worth bearing in mind that the right to marry is a Convention right as well, and all EU member states are parties to the Convention in addition to the Charter. So you might find some useful Strasbourg jurisprudence on this too.
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As I said it’s a long way from my area of expertise, but I would interpret this as a question about Member States’ ability to derogate from an EU charter right (the right to marry). In other words, the EU charter safeguards certain fundamental rights of EU citizens, including the right to marry. So has the ECJ said anything about the ability of member state governments to interfere with / derogate from that right (for example, by charging fees, or making people have covid tests). I have no idea what the answer is, but that’s how I would approach it.