CSG-CRDS and health contributions for cross-border workers: who pays what, and where to declare it

"Do I pay CSG?" is one of the questions cross-border workers ask most often, and one of the worst served — because it mixes up three levies that share neither a legal basis, nor an assessment base, nor a recipient. This guide separates the three: CSG-CRDS, which does not touch your Swiss salary but may touch your French assets; the cross-border worker health contribution, which Urssaf charges if you opted for French cover; and the LAMal premium, if you stayed insured in Switzerland. The choice between those last two regimes is covered in our guide on choosing between LAMal and cover in your country of residence; here we look at what each one actually costs and where it is declared.

1. Why does your Swiss salary escape CSG-CRDS?

Because you fall outside the scope of the contribution. The tax doctrine published in the French official tax bulletin is explicit: "The general social contribution (CSG) provided for in article L. 136-1 of the social security code is due on earned income and replacement income received by persons who are tax resident in France and covered by a compulsory French health insurance scheme." Both conditions apply together, and it is the second one that makes all the difference for a cross-border worker.

The principle behind it all: you are subject to only one social security system

European regulation 883/2004 on the coordination of social security systems, extended to Switzerland by the free movement of persons agreement, sets out a single-state principle in its article 11: at any given time a person is subject to the legislation of one state only, in principle the state where they work. A French resident employed in Switzerland is therefore subject to Swiss social security for their work — which is precisely why their AVS, AI and LPP contributions are withheld on their Swiss payslip and not in France.

That principle has a direct consequence for CSG. In the de Ruyter judgment (C-623/13), the Court of Justice of the European Union held that CSG and CRDS, despite being classified as taxes under French domestic law, fall within the scope of the regulation because they help finance the French social security system. They cannot therefore be levied on someone who belongs to another system. The French Conseil d'État confirmed and extended that reading, notably in decision no. 422780 of 1 July 2019.

What if I opted for French health insurance?

You then become affiliated to the French general scheme for your health cover, under article L380-3-1 of the social security code. What Urssaf charges you each year is still not CSG: it is a health insurance contribution, with its own rate and its own base, set out in the next section.

One detail of the Urssaf declaration form confirms that this levy is not CSG. In the "other income" section, the official guide asks for amounts to be entered "after deducting the amount of CSG" — because that income, rental income or investment income, genuinely bears it. In the "salaries" section, that deduction appears nowhere. There is nothing there to deduct.

Who pays what, depending on your situation

2. What exactly does the health contribution cost?

Urssaf publishes the formula, and it leaves no room for interpretation: contribution = (assessment base − allowance of 25% of the social security ceiling) × 8% × number of days ÷ 365. The calculation base and the contribution are both rounded to the nearest euro.

The base is not your reference tax income

This is the most widespread error on the subject, including in otherwise serious content. The annual declaration you complete in your Urssaf account has three sections: net salaries, pensions and annuities; other income; and the reference tax income. The official guide sets out the role of each: "The sum of the first two sections is what your contribution is calculated on. The reference tax income is not taken into account in the calculation of your contribution, it serves only as a verification basis."

The distinction is not academic. The reference tax income is an aggregate for the tax household, whereas the Urssaf declaration is individual: if your spouse is also a cross-border worker covered in France, you each declare your own income and you each get your own allowance of 12,015 euros. As for income received jointly within the household, the guide asks for half of it to be declared.

What goes into the base, and what comes out

Calculator: your cross-border worker health contribution

This calculator applies the official Urssaf formula, including the pro rata by days of affiliation that matters when you start or end a job during the year. Use it to check a contribution notice you have received, or to anticipate next year's from your income of two years earlier.

3. And if you stayed with LAMal, what do you pay?

A premium, not a contribution. The difference is structural: the French contribution depends on your income and covers your dependants at no extra cost; the Swiss premium does not depend on your income at all, but is charged per insured person. The Swiss Federal Office of Public Health puts it this way: "Anyone who works in Switzerland, as well as members of their family without gainful employment, must take out health insurance there." A spouse who works in France is covered by their own job and is not concerned.

Insured people living in a European Union or EFTA state pay the premiums applicable to their country of residence. There is therefore a premium scale specific to France, approved each year by the Federal Office of Public Health.

2026 premiums for insured people living in France

Here is the official scale for an adult, with the basic deductible of 300 francs and without accident cover — the variant that applies to an employed cross-border worker, since accident risk is already covered by their Swiss employer's compulsory insurance.

Monthly premiums in Swiss francs for insured people living in France, 2026 premium year, basic insurance without accident cover, 300-franc deductible for adults and young adults, no deductible for children. Source: Swiss Federal Office of Public Health, EU/EFTA premium report, data retrieved on 16 September 2026.

Three levers can bring the premium above down: the choice of insurer, the deductible level and the insurance model. We have put figures on all three, including the tipping point beyond which a high deductible stops paying off, in our guide to Swiss health insurance deductibles and models. And if you are wondering what LAMal reimburses when you are treated on the French side of the border, the answer is in our guide to LAMal cover abroad and the S1 form.

4. Why does CSG-CRDS come back through your rental income?

Because CSG does not only hit earned income. It also hits French-source investment and rental income — rents, life annuities, capital gains — and on that ground the exemption rule is narrower than for salary. If you own a flat let out in Haute-Savoie or the Pays de Gex, this is the section that weighs most heavily on your annual budget.

The applicable rates

The French tax authorities state the rule as follows: "Rental income received by persons covered by a health insurance scheme of a State of the European Economic Area, the United Kingdom or Switzerland and not covered by a compulsory French social security scheme is not subject to CSG and CRDS on investment and rental income. Such persons do, however, remain liable to the solidarity levy at the rate of 7.5%."

The two conditions for box 8SH, and why they are not equal

The supplementary return 2042-C repeats those two conditions word for word, under the heading "Investment and rental income exempt from CSG and CRDS": "You are covered by a health insurance scheme of a State of the European Economic Area, the United Kingdom or Switzerland and you are not covered by a compulsory French social security scheme", box 8SH for the first taxpayer, box 8SI for the second.

A cross-border worker who stayed with LAMal meets both without argument: they are insured in Switzerland, and they are covered by no French scheme. A cross-border worker who opted for French health insurance meets the first but not the second, since affiliation to the general scheme is precisely what puts them in the care of a compulsory French scheme. On the letter of the form, they therefore cannot tick the box.

Mixed couples: the case where one box is not enough

This is the most common set-up around Lake Geneva: one partner works in Geneva, the other in Annemasse or Ferney-Voltaire. The form then provides for a split, and its wording is unambiguous: "Only fill in the boxes below if you are married or in a civil partnership and only one of the two spouses meets the condition above." You then have to enter the exempt investment and rental income in the dedicated boxes, notably 8RF for rental income after the allowance under the simplified regime and 8RV for life annuities for consideration. Income that remains subject to social levies goes in 8TQ and the following boxes.

Two useful points: affiliation is assessed as at 31 December of the year the income was received, and the split only applies in that specific case — if both spouses meet the condition, ticking boxes 8SH and 8SI is enough.

Calculator: your social levies on investment and rental income

This calculator compares what you owe depending on whether or not you meet both conditions for box 8SH. It does not prejudge your situation: it puts a figure on what is at stake, so you know what you are asking about when you contact your tax office.

5. Where to declare what: 6DD, income category, 8SH

Three amounts, three different places, and putting one in the wrong box can cost several hundred euros in tax. The tax authorities draw a clear distinction between Swiss premiums and the French contribution: "The Swiss LAMal premium is deductible from the income category, that is, directly from the amount of your Swiss-source salary or pension", whereas "the contribution paid to the Cross-Border Workers in Switzerland Service (URSSAF/STFS) is deductible from your total income and must be entered on line 6DD "Other deductions" of your general income tax return (form 2042-C)".

Line 6DD is headed "other deductions" and sits in the section for deductions provided for by articles 156, II and 156 bis of the French general tax code. Just below it the form provides a "Nature of deductions" field: state the cross-border worker health contribution there explicitly, otherwise the deduction may be challenged. For the other deductions a cross-border worker can claim, and for the tax credit that neutralises double taxation, see our guide to cross-border worker tax deductions, as well as our general guide to cross-border worker taxes.

6. What changes when your situation changes

The right to choose between Swiss and French health insurance is exercised within three months of starting work in Switzerland. Without any step on your part, you are automatically insured under Swiss health insurance. The request goes through the "Choice of health insurance system" form, which you first hand to the health insurance fund covering your place of residence, then, once endorsed, to the competent cantonal authority of the canton where you work.

Be careful how that choice commits you. Urssaf words it precisely: "If you opt for French health insurance and you are an employee, you will not be able to switch to Swiss health insurance for the entire duration of your employment contract." The circumstances in which a change of situation genuinely reopens that choice are set out in our dedicated guide: changing health insurance as a cross-border worker.

7. The line everyone forgets: the cost of conversion

One practical difference separates the two regimes, and it appears in no scale. The LAMal premium is paid in Swiss francs, the same currency as your salary: no conversion is needed, the money never crosses the currency border. The Urssaf contribution is paid in euros, while your income is in francs: every year, something has to be converted.

The order of magnitude is easy to set out. On 72,000 euros of declared income, the annual contribution comes close to 4,800 euros. A gap of one and a half points between the interbank rate and the rate applied by your provider represents about 72 euros a year on that line alone — modest next to the 9.7 points at stake on rental income, but it adds to the same gap borne every month on the salary itself. That is the subject of our guide on transferring your Swiss salary abroad, and you can follow the live rate on our CHF-EUR converter.

ibani is a Geneva-based financial intermediary specialising in transfers between Switzerland and the euro area, with a personal Swiss IBAN: the salary arrives in francs, the conversion happens when you choose, and the transfer goes to the euro account that will pay Urssaf. Our cross-border worker service page explains how it works.

8. Frequently asked questions