The 5 mistakes new Swiss cross-border workers make, and the deadlines you cannot recover

Guides for new cross-border workers usually begin with the G permit and opening an account. Those steps at least have the merit of being visible: you take them because you cannot start work without them. The mistakes that genuinely cost money are of another kind — they are administrative windows that close without a sound, and deductions that never carry the name of a fee.

In this guide:

• 1. Letting the three months of the right of option run out
• 2. Missing 31 March
• 3. Crossing the telework thresholds without knowing it
• 4. Declaring the Swiss account incorrectly
• 5. Paying an exchange margin you have never measured
• 6. What belongs in your diary
• 7. Frequently asked questions

1. Letting the three months of the right of option run out

This is the most final mistake of the five. On taking up employment in Switzerland, a cross-border worker resident in France chooses their health insurance scheme between the Swiss LAMal and the French system. That choice has a name — the right of option — and a feature many discover too late: it is in principle irrevocable.

It reopens only on an exhaustively listed change of circumstances, and the precision of each one matters:

• taking up employment in Switzerland again, in particular after a period of French unemployment benefit — it is the return to work that reopens the right, not the loss of the job;
• moving from Switzerland to France — a move within the country of residence reopens nothing;
• retiring on a pension that is exclusively Swiss — drawing even the smallest French pension generally closes that door;
• since 2026, recognition of a disability giving rise to an AI pension — a development reported in our dedicated guide, to be confirmed with your insurance fund before taking any step.

In those cases, you have a strict three months to act. After that deadline, LAMal affiliation applies automatically.

Residents of Italy and Germany have a comparable exemption right, but under arrangements specific to each agreement: the reopening events and deadlines described here do not transfer to them as they stand. The detail of the events that reopen the right, and of the exact steps, is set out in our guide on changing a cross-border worker's health insurance.

2. Missing 31 March

If you are taxed at source in Switzerland, two separate procedures allow you to recover tax, and both must be filed before 31 March of the following year. This is a forfeiture deadline, not an indicative one: afterwards, nothing can be recovered.

In both cases, filing must take place before 31 March of the following year.

The most common trap is believing that only quasi-residents have anything to recover. That is false: a scale error — a child not taken into account, a marital situation wrongly recorded, a second job mis-declared — is corrected by a simple request, with no income condition, no accountant and no special status.

Quasi-resident status, for its part, allows you to deduct actual expenses — third pillar, childcare, continuing education — rather than accept the flat allowance built into the scale. One warning, however: since 2021 that choice is irrevocable, and if your actual expenses are lower than the flat allowance, the request works against you.

31 March applies to anyone taxed at source in Switzerland. Filing arrangements, however, are cantonal: our guides set out the Geneva procedure and quasi-resident status.

3. Crossing the telework thresholds without knowing it

The tolerance period opened during the pandemic is over. Cross-border telework is now governed by two distinct thresholds, which come from different texts and do not trigger the same consequences. It is that duality which produces the mistake: people remember one figure and ignore the other — and forget that the tax threshold is not the same depending on the country of residence.

The threshold that stops you first is therefore the tax threshold. For a resident of France or Germany, two days of telework a week represent exactly 40% of a full-time week: there is no margin, and one exceptional three-day week is enough to tip the annual average if nothing offsets it. For a resident of Italy, the 25% ceiling is reached after one and a quarter days a week — in practice, a single day of telework per week.

The detail of the rules, the supporting documents and the special cases is set out in our guide on cross-border telework.

4. Declaring the Swiss account incorrectly

This is the mistake where generalising costs the most, because the three countries of residence do not require the same thing.

For a French tax resident, the obligation is broader than most imagine: it covers every account opened, held, used or closed abroad, whatever its balance (article 1649 A of the French tax code). Three words deserve attention. Held: a dormant account must be declared. Used: an account you are not the holder of but do operate must be declared too. Closed: in the year it is closed, it is declared one last time.

The "they will never know" argument stopped working long ago: Switzerland automatically exchanges banking information with France, Italy and Germany. Non-declaration is not a detection risk, it is a discrepancy already visible. Our guide on opening a Swiss bank account sets out each case.

5. Paying an exchange margin you have never measured

The first four mistakes are made once. This one repeats twelve times a year, and it is the only one whose cost keeps running for as long as you have not measured it.

The mechanism is simple: when francs are converted into euros for you, the intermediary's remuneration is most often built into the rate applied, rather than charged separately. That is why a conversion can be presented as "fee-free" while costing more than another that displays a commission.

Assumption: a salary of 5,000 CHF converted each month. The cost is proportional to the amount converted.

Measuring it takes no tool: note the interbank rate at the time of the transaction, compare it with the rate you were given, and relate the gap to the amount. It is that gap, not the fees on display, which determines what the conversion cost you. Our exchange rate comparison sets out the differences observed between providers.

6. What belongs in your diary

Four of the five mistakes come down to a deadline. Two of them fit into a date; the other two into a habit.

7. Frequently asked questions

What are the most expensive mistakes for a new Swiss cross-border worker?

The two most expensive are the ones that lapse: letting the three months of the health insurance right of option run out, and missing 31 March for the withholding tax correction. The other three cost for as long as they last: telework thresholds can be corrected for the future, but the past is reassessed; the account declaration and the exchange margin can be taken in hand at any time. This information is provided for guidance only and does not constitute personalised advice.

Is the health insurance right of option final?

It is in principle irrevocable. For a cross-border worker resident in France, it reopens only on taking up employment in Switzerland again, moving from Switzerland to France, retiring on an exclusively Swiss pension, or, since 2026, recognition of a disability giving rise to an AI pension — to be confirmed with your insurance fund. You then have a strict three months to act; after that deadline, LAMal affiliation applies automatically.

What happens if I miss 31 March for my tax correction?

Nothing can be recovered. 31 March of the following year is a forfeiture deadline, not an indicative one: neither the correction of a wrong scale nor the request for a subsequent ordinary assessment can be filed after it. It is the easiest deadline to neutralise, since it only has to be written in your diary once.

Do you have to be a quasi-resident to request a tax correction?

No, and that is the most widespread misunderstanding. Correcting a wrong scale — a child not taken into account, a marital situation wrongly recorded, a second job — requires no income condition and no special status. Quasi-resident status is a separate procedure, subject to an additional condition: at least 90% of the household's gross worldwide income taxable in Switzerland.

What is the telework threshold a cross-border worker must not exceed?

It depends on your country of residence, and there are two of a different nature. On the tax side: 40% of working time for a resident of France or Germany, 25% for a resident of Italy. On the social security side, the 49.9% threshold comes from the multilateral framework agreement under the AFMP. The tax threshold is reached first, so it is the one that governs in practice.

Are the telework thresholds the same for every cross-border worker?

No. This is one of the most frequent misreadings: most articles online describe the France-Switzerland framework and quote 40% without specifying the country. A resident of Italy, whose tax ceiling is 25%, would exceed that ceiling by fifteen points by following that figure. Always check which country of residence the threshold you are reading refers to.

Does a Swiss bank account have to be declared even without interest?

For a French tax resident, yes: every account opened, held, used or closed abroad must be declared, whatever its balance, on form 3916-3916 bis (article 1649 A of the French tax code). Germany does not require the account's existence to be declared but does require capital income to be reported in the Anlage KAP. Italy only triggers the quadro RW above 15,000 euros of maximum daily balance.

What is the penalty for an undeclared Swiss account?

1,500 euros per account and per undeclared year for a French tax resident. The figure of 10,000 euros sometimes quoted does not apply to Switzerland: it concerns accounts held in a country without an administrative assistance convention. Bear in mind that Switzerland automatically exchanges banking information with France, Italy and Germany. The amount falls under applicable French law: have your situation checked with the relevant authority.

How do I find out what my currency exchange really costs?

Note the interbank rate at the time of the transaction and compare it with the rate you were given. The gap, related to the amount converted, is the real cost — the fees on display are only part of it, and usually the smaller part. On a salary of 5,000 CHF converted each month, one and a half points of margin comes to roughly 900 CHF a year.

A salary in francs, spending in euros?

The first four mistakes are settled with a diary, two forms and a count. The fifth comes back every month, for as long as you let it run. It is also the easiest to take in hand, precisely because it never announces itself as a cost.

Sources. Accounts held abroad: article 1649 A of the French tax code, form 3916-3916 bis; quadro RW of the Modello Redditi and IVAFE for Italy; Anlage KAP for Germany. Telework: 2023 amendment to the France-Switzerland tax treaty for the French tax threshold, multilateral framework agreement under the AFMP for the social security threshold. The exchange costs shown are calculations based on an explicit assumption, not observed price lists.

Further reading. The rules of the right of option and the three-month deadline, the cantonal arrangements for the withholding tax correction, the conditions of quasi-resident status and the reporting thresholds by country are developed in the guides linked throughout this page.

This article is provided for information only and constitutes neither tax advice, nor insurance advice, nor personalised advice. Rules change and individual situations differ: for a decision that commits you, have your case reviewed by a professional or by the relevant authority.