This is all central to the Minsk11 agreement which was brokered in 2015 by France and Germany there was 13 points that needed to be implemented which haven’t been done by Ukraine and the separatist that annexed Crimea.
The separatists who are not Russia but Russian backed believe that one of the 13 points gains them a seat in the Ukrainian Parliament, which means they would have a veto to stop all Ukrainian foreign policies, one being a full membership of NATO Ukraine dispute this as they see NATO as the only real defence from Russian aggression now and in the future.
It’s all pretty complicated and the French and Germans have pretty much fucked up by allowing to many of the points to be construed differently by both sides.
But instead of backing Ukraine in there interpretation of the agreement they are backing the separatists and the Russians by saying after the meeting with Putin that they need to implement Minsk11 fully giving power to the Russians to control Ukrainian foreign policies, the Ukrainians said no were are an independent country and won’t give up political control of their country.