Nobody knows. If Brexit goes ahead I think they will go down in the countryside when the British leave and stop buying in France because it will be more difficult for them. On the other hand there may be a huge exodus of people leaving a sinking right-wing UK. On Twitter many are talking of leaving - lots going to Scotland if it becomes independent and remains in the EU. On the other hand, the British have always had a holiday cottage in France so perhaps they won't be put off. I would wait and see what happens in October. If I had money to invest in property right now I'd be looking at Scotland!