Trip Insurance in case of closure

Well, be sure you know what "cancel for any reason" means to your chosen company. I think this is a time that you need to talk with someone to ask questions. I was shocked a few years ago when I found out that CFAR didn't actually mean ANY reason. Also check to see how much you'll get back. Typically policies will refund only 50-75% of prepaid costs.

How much prepaid stuff do you have booked that you couldn't cancel?

Mainly a week in a VRBO in Paris, another one in the Loire, and a rail pass for 6.

I wonder if the first step would be to contact the VRBO host and ask what their policy would be on a refund if you were not allowed to enter the country. You may find that insurance wouldn't be necessary or discover that you absolutely will need it. I would start there.

Lots of insurance will not cover COVID -- they have a blanket force majeure exemption that covers war, terrorism and pandemics among other things. I would not assume insurance will cover these losses unless you buy specific insurance that clearly says in writing it covers such losses. It might be difficult to get that in an upsurge like the current new variant. And of course, all travel insurance has to be purchased immediately upon first booking any arrangements. It isn't something you can add well after booking flights and apartments.

Let us know if you find a policy that works for this.

I just purchased travel insurance via Cover More (Zurich company). Here’s what it says regarding Covid:
Covid-19 is treated like any other illness under the policy and is subject to all the same benefits, limitations, and exclusions listed in the policy details. If quarantined at your destination, coverage will automatically extend to the date you reach your return destination and benefits will be paid up to the policy limits, as long as you return as soon as you are fit to fly or once your quarantine period is over.

Although I purchased it 3 weeks before departure and some benefits I don’t think have (cancel for any reason due to when I purchased my trip), I found it worth having some protection. It cost $525 for our family of 5.
Just the risk of Covid and quarantine is in itself valuable.

Many French rail tickets and passes are either partly or fully refundable before the scheduled travel date, but that is yet another place to read the fine print before purchase.

We bought an annual plan for a family of 4 through Allianz.

https://www.allianztravelinsurance.com/find-a-plan