I imagine it'll be mainland Europe only if it does go ahead, due to quarantine regulations with international travel. I wonder how they're going to handle refunds if that's the case. Being from the UK I better give them a call to find out.
I would think that would be more a governmental decision than a business one, which could mean unless France is restricting access, Disney might not be obligated to provide refunds. Our borders with France will open next month.