Cross-border worker: Luxembourg top-up, home-country plan or both?

Two countries, two health funds

As an employee or self-employed person in Luxembourg, you are affiliated to the CNS through the Joint Social Security Centre. As a cross-border worker, you are entitled to care in Luxembourg on the same terms as a resident, and in your country of residence, provided you register with its health fund using the form issued by the CNS:

• France: form S1/S072 opens your rights with the CPAM. In the Grand Est départements (Ardennes, Aube, Marne, Haute-Marne, Meurthe-et-Moselle, Meuse, Moselle, Vosges, Bas-Rhin, Haut-Rhin), it is sent straight to the CPAM; elsewhere, it arrives at your home and you forward it. The CPAM then issues a carte Vitale.
• Belgium: form BL1, to hand to the mutualité of your choice.
• Germany: form S1, to send to the statutory health fund (gesetzliche Krankenkasse) you choose.

If no form has arrived 15 days after you receive your registration confirmation from the Joint Social Security Centre, order it online from the CNS. For your family, the law of your country of residence decides who counts as a dependant: in France, the CPAM itself asks the CNS to register them, so simply check that it has done so.

Who reimburses what

Luxembourg rates are detailed in our table of CNS reimbursements.

Choose your top-up on the side where you are treated

A top-up plan fills the gap between actual costs and what the basic scheme reimburses. But the basic scheme is not the same on both sides of the border. Hence the rule: look at where you really get care, your GP, your dentist, the hospital where you would have surgery.

• Mostly treated in your country of residence: a local plan, such as a French mutuelle, is built to complement that country’s fund. Before signing, ask what it provides for care received in Luxembourg and reimbursed by the CNS.
• Mostly treated in Luxembourg: a Luxembourg top-up plan starts from CNS reimbursements. According to its 2026 statutes, the CMCM is open to anyone insured with a Luxembourg health fund and living in Luxembourg or a neighbouring country: no medical questionnaire or age limit, family co-insured at no extra cost, three-month waiting period. It covers the balance left by the CNS, first class with PrestaPlus, dental and eyewear with Denta & OptiPlus, and offers direct billing in its partner hospitals in France, Germany and Belgium for referrals to a specialist.
• Among Luxembourg private insurers, two examples: Foyer offers French residents direct billing and electronic claims with its medicis plan, through its partner Novamut; AXA opens OptiSoins to cross-border workers covered by the CNS, with free choice of doctor and hospital in Europe subject to prior agreement. See our Foyer and AXA profiles.

What about both?

If you split your care between the two countries, combining a home-country plan for everyday care and a Luxembourg plan for hospital or dental care in Luxembourg can make sense. Do the maths on your actual spending: add up both annual premiums and compare them with what each would reimburse over a typical year. Note for the CMCM: for a member living in a neighbouring country, its assistance abroad only applies more than 50 km from home.

Tax and sick leave

• Deduction: top-up health premiums count towards the €672 per household member ceiling of article 111, if you are taxed in Luxembourg as a resident or as an assimilated non-resident (article 157ter). Our article on tax deductions sets out the conditions.
• Sick leave: send the original certificate to the CNS before the end of the third working day, with your 13-digit Luxembourg identification number, even if your doctor is abroad.

For car, home and pension cover, see our guide to the four insurance policies to check as a cross-border worker.