The problem is that we are in the ‘inbetween’ stage at the moment. The virus is not widespread enough in Europe to render all attempts to contain/slow it useless. So in the next couple of weeks we could conceivably get more hotspots like Lombardy popping up and getting quarantined, including your destination region.
I can’t see France shutting borders with the UK in your timescale, and if it were that rampant in either country, then it would most likely be rampant in both.
You need to check the t&cs of your insurance, and probably speak to your insurer to confirm.
It’s also possible, if you are very unlucky, that you could get stuck there, or even subject to quarantine on your return, if the region you’re visiting has an outbreak while you’re there.