You are UK retirees? And do you have your State Pensions yet? As if so, even after Brexit you can apply for something called an S1 that means that the UK pays for you to join the French Health Care system.
It can take a little bit from arriving here to getting it all sorted, so you do need a short period of PHI.
Alternatively, if not yet in receipt of your UK State Pension you can join the health service after you have been here for 3 months. And it also take a bit to get this all sorted, so you are looking at PHI for maybe 6 months.
Once in the health service either you pay nothing (with an S1) or you pay about 8% of your income above about €10,000. Much cheaper than PHI!
The French Health Service isn’t 100% free. You have to pay a percentage for every medical act. This varies from 0-100% just to make it more complicated! Many people take out what is called a mutuelle, or top up insurance, to cover this element. It’s a choice.
It’s a thorny subject that’s particularly French. So hope this helps!