Before you start

A residence permit or validated visa
Proof of stable residence in France
Employment contract or proof of activity, for the fastest route
A French bank RIB, for reimbursements

Step-by-step

1
Start the social security registration immediately
If employed, your employer initiates it, but the process is slow and you should track it. The number is what everything else hangs off. Expect months rather than weeks and do not read the delay as a sign something has gone wrong.
Via employerWho: You and your employerWeek 1
2
Keep every feuille de soins until the card arrives
Until you have a carte Vitale you pay in full and submit a paper claim form the doctor gives you. Keep them all — reimbursements are backdated once you are in the system, and people routinely lose several hundred euros by discarding paperwork from their first months.
In personWho: You
3
Declare a médecin traitant as soon as you can
Naming a family doctor with the health insurance fund raises your reimbursement rate and is the gateway to specialists. Consulting outside that pathway is reimbursed at a materially lower rate, permanently.
In personWho: You
4
Get a mutuelle, and check whether your employer provides one
The state reimburses most but not all of a consultation, and covers dental and optical care poorly. A complementary insurer fills the gap. Employers are generally required to offer a scheme and fund at least half of it, and almost everyone in France has one.
Via employerWho: You
5
Create an Ameli account once you have a number
The online account is where reimbursements, attestations and your card status live. The attestation de droits it produces is another document you will be asked for repeatedly.
OnlineWho: You
6
Keep private or travel cover for the gap period
The months between arriving and having a working carte Vitale are a genuine exposure. Keeping a private policy for that window is a sensible precaution and much cheaper than the alternative.
OnlineWho: You

Documents you’ll need

Residence permit or validated visa
Birth certificate with a sworn translation, frequently required
Employment contract or proof of activity
Justificatif de domicile
RIB for reimbursements

Things most newcomers don’t know

Keep every paper claim form from your first months — they are money.

Before the carte Vitale arrives you pay in full and receive a feuille de soins to submit on paper. Once your file is active those claims are reimbursed retroactively. New arrivals throw them away because nothing seems to be happening, and lose several hundred euros of legitimate reimbursement they cannot reconstruct.

Source: l'Assurance Maladie

Not declaring a médecin traitant costs you on every consultation, permanently.

The reimbursement rate within the coordinated care pathway is substantially higher than outside it, and until you have named a family doctor you are outside it. Doctors accepting new patients can be hard to find in parts of Marseille, so start in your first weeks rather than when you first fall ill.

Source: l'Assurance Maladie

A translated birth certificate is the document that stalls files.

French social security registration frequently requires a full birth certificate, sometimes recent, translated by a court-approved translator. Obtaining one from another country takes weeks and it is the most common reason a registration file sits unprocessed. Start this before you leave rather than once you are asked.

Source: l'Assurance Maladie

Almost everyone has a mutuelle, and going without is a real cost.

The state covers most of a consultation but not all, and covers dental and optical care poorly. Complementary insurance is close to universal in France and employers must offer a scheme and fund at least half. Declining it to save the premium is a false economy for anyone who uses healthcare at all.

Source: service-public.fr

Common mistakes to avoid

Discarding paper claim forms before your file is active.
Not declaring a médecin traitant and paying the reduced rate indefinitely.
Arriving without a translated birth certificate and stalling registration for weeks.
Declining the employer mutuelle without understanding what the state does not cover.
Letting private or travel cover lapse before the carte Vitale actually works.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.