Health insurance is an insurance that covers the whole or a part of the risk of a person incurring medical expenses, spreading the risk over a large number of persons. By estimating the overall risk of health care and health system expenses over the risk pool, an insurer can develop a routine finance structure, such as a monthly premium or payroll tax, to provide the money to pay for the health care benefits specified in the insurance agreement. The benefit is administered by a central organization such as a government agency, private business, or not-for-profit entity.
Today, this system is more or less intact. All citizens and legal foreign residents of France are covered by one of these mandatory programs, which continue to be funded by worker participation. However, since 1945, a number of major changes have been introduced. Firstly, the different health care funds (there are five: General, Independent, Agricultural, Student, Public Servants) now all reimburse at the same rate. Secondly, since 2000, the government now provides health care to those who are not covered by a mandatory regime (those who have never worked and who are not students, meaning the very rich or the very poor). This regime, unlike the worker-financed ones, is financed via general taxation and reimburses at a higher rate than the profession-based system for those who cannot afford to make up the difference. Finally, to counter the rise in health care costs, the government has installed two plans, (in 2004 and 2006), which require insured people to declare a referring doctor in order to be fully reimbursed for specialist visits, and which installed a mandatory co-pay of €1 for a doctor visit, €0.50 for each box of medicine prescribed, and a fee of €16–18 per day for hospital stays and for expensive procedures.
Most provider markets (especially hospitals) are also highly concentrated—roughly 80%, according to criteria established by the FTC and Department of Justice—so insurers usually have little choice about which providers to include in their networks, and consequently little leverage to control the prices they pay. Large insurers frequently negotiate most-favored nation clauses with providers, agreeing to raise rates significantly while guaranteeing that providers will charge other insurers higher rates.
Medicare Supplement policies are designed to cover expenses not covered (or only partially covered) by the "original Medicare" (Parts A & B) fee-for-service benefits. They are only available to individuals enrolled in Medicare Parts A & B. Medigap plans may be purchased on a guaranteed issue basis (no health questions asked) during a six-month open enrollment period when an individual first becomes eligible for Medicare. The benefits offered by Medigap plans are standardized.