Three months after your first day at work in Switzerland, the question of your health insurance has been settled — by you, or for you.
A person who lives in France and takes a job in Switzerland has a right of option. They can join Swiss compulsory health care insurance, known as the KVG in German and the LAMal in French, or stay with French health insurance; this second route is what everyone calls “the CMU”. The three-month deadline runs from the start of the employment contract, and if you do nothing, you are automatically insured in Switzerland.
A choice that only reopens if your situation changes
The French body for European and international social security liaison (Cleiss) is clear: the right of option can be exercised only once and is irrevocable. It reopens only if you resume work in Switzerland, for example after a period of unemployment, if you move your residence to France, or if you retire with a pension from the Swiss system alone. A change of employer is not on that list, and nor is a premium increase the following year.
Form matters as much as substance. The Federal Office of Public Health (FOPH) specifies that a formal application for exemption from compulsory insurance in Switzerland must be made, and points out that the Federal Supreme Court ruled in 2015 that a right of option exercised tacitly is not valid. In Geneva, this is done with the right-of-option form, stamped by the local French health insurance fund (caisse primaire d'assurance maladie, CPAM) where you live, then sent to the canton's health insurance service.
Treatment on both sides of the border, or only one
This is often the most tangible difference day to day. According to the Canton of Geneva, cross-border workers insured under the LAMal have a free choice of where to be treated and can receive care in Switzerland as well as in France.
Cross-border workers who stayed with French social security can only access care in Switzerland in an emergency. For major treatment planned in advance in Switzerland, the French Assurance Maladie requires prior authorisation, given on form S2. For someone who spends their days in Geneva, seeing a doctor near work is therefore not an ordinary option.
A premium per person, or an income-based contribution
The KVG/LAMal is paid per person. Each insured person has their own premium, set by the insurer, and for people living in a European Union state it is the premium for their country of residence that applies, not that of the canton where they work. Your salary plays no part in the calculation. Depending on your income, however, you may be eligible for subsidies that reduce the premium.
French health insurance works the other way round. The contribution is calculated by the Urssaf's national centre for Swiss cross-border workers, on income from the year before last: 8% of the portion above an allowance equal to 25% of the annual French social security ceiling. In 2026 that ceiling is EUR 48'060, which puts the allowance at EUR 12'015.
Two consequences follow. The more you earn, the higher the contribution, whereas the LAMal premium does not move with salary. And because the base is two years old, a rise in income feeds through late, and so does a fall, which can complicate the first few years after a change of job.
When the family tips the balance
The French contribution covers the insured person and their dependants. A spouse with no income and children living in France are therefore covered by that same contribution, with no extra charge per person.
On the Swiss side, family members without gainful employment must also be insured, and each has their own premium. The Cleiss also points out that, for family members living in France, health cover depends on the option you choose: your choice commits them along with you.
A single person on a high salary and a family living on one income will therefore not necessarily reach the same answer.
Pros and cons, system by system
Swiss health insurance (KVG/LAMal)
- Pro: free choice of being treated in Switzerland or in France.
- Pro: a premium that does not depend on salary, which matters more as income rises.
- Pro: possible subsidies, depending on income, to reduce the premium.
- Con: a premium for every insured person, which quickly adds up in a family.
- Con: Swiss supplementary insurance falls under the VVG/LCA, and the insurer can turn the application down or accept it with a reservation.
French health insurance (“CMU”)
- Pro: a single contribution for the insured person and their dependants.
- Pro: a cost proportional to income, which stays modest when income is only just above the allowance.
- Pro: the option of taking out a French top-up health policy (complémentaire santé) for the share of costs left for you to pay.
- Con: a contribution that rises with salary.
- Con: in Switzerland, care limited to emergencies, and prior authorisation for planned major treatment.
- Con: a calculation based on income from two years ago, which can come as a surprise after a pay rise.
Before the end of the third month
The timetable is the least forgiving part. Once the deadline has passed, affiliation in Switzerland is automatic, and the Canton of Geneva states that it can be cancelled only under certain conditions. Deciding during the first month leaves time to have the form stamped by the CPAM and to send it with proof of posting.
To compare, start from your actual situation rather than from the names of the systems: your income from two years ago, the number of people to insure, and where you get medical care today.