When applying for your initial long-stay visa for your first year in France and then to remain staying in the country beyond that, you must prove that you have health insurance for your whole stay. This is one of those items that differs from one consulate to another. One will simply state that you must have health insurance while another will be very specific telling you, for example, that there must be a zero deductible with a minimum $50,000 coverage with expatriation to the US included. Some will even list the names of insurance companies that they will accept.
There are two types of insurance that might satisfy this requirement based on the needs of your consulate. Traditional travel insurance that you would get to cover a canceled vacation, lost luggage, car rental damage waiver, etc. often includes adequate medical coverage including repatriation and can often be bought to cover a trip of 364 days.
The other is called either international or expat health insurance and is meant to be exactly that: health insurance that you would have in your own country without travel-related coverage for things like lost luggage. From comments that I’ve seen online, it seems that many people get a one-year travel insurance policy for their initial visa application and then switch to international insurance for their second year in France. After that they apply for national health insurance from the French government.
After living in France for three months, a resident can apply for national health insurance that covers 70 percent of the standardized medical fees and can buy separately a private policy that covers the additional 30 percent. There is no guarantee that an applicant will be accepted; however, if accepted you must begin paying for the insurance. People earning a salary pay through their employer. Retirees and other non-wage earners pay the government directly a fee of 8 percent of the household’s annual income minus an exemption of around 9000 euro. You must provide the insurance authority with your previous 2 year’s income tax returns (the US and France do share information) so if your income will drop after your first year in France, perhaps due to transitioning from a full-time job to collecting a pension for example, it might be cheaper to buy the private international insurance until your income levels out.