Heidi › Cross-border workers
How many days of remote work can I do without losing my cross-border worker status?
40% of your annual working time, which is about 88 days a year or 1.7 days a week. Above that, the share worked remotely becomes taxable in France.
But there is a second threshold, which many people confuse with the first: on the social security side, the limit is 49.9% — and only if your employer has applied for the A1 certificate. Without it, the limit drops to 25%.
So your real ceiling is the lowest of the thresholds that apply to you. For most cross-border workers with an A1 certificate, it is 40%. Without an A1 certificate, it is 25% — a single day a week.
The tax threshold
About 88 days a year. In force since 1st January 2026.
The social security threshold
With an A1 certificate. Without it, only 25%.
Three thresholds, not one
| Threshold | What it protects | If you go over it |
|---|---|---|
| 40% Tax |
Your salary stays taxed in Switzerland | The days worked remotely become taxable in France |
| 49.9% Social security, with an A1 |
You stay with Swiss AVS and your Swiss pension fund | You switch to French social security |
| 25% Social security, without an A1 |
The same thing, but this is the default rule | You switch to French social security |
It comes from a European framework agreement that Switzerland signed up to, and it only applies if your employer applies for an A1 certificate for you. It is a step someone has to take, not a right that kicks in by itself.
Without that certificate, the basic rule comes back: beyond 25% of your work done in France, you change social security system. And changing social security system is no formality — your pension, your benefits and your cover all change country.
The calculation, in one line
40% × 220 working days = 88 days a year
That is 1.7 days a week on average. The percentage is worked out over the year, not week by week.
| Counts as remote work | Does not count |
|---|---|
| A day worked from your home in France | Holiday, time off in lieu, public holidays and sick leave |
| A day from a café or a coworking space in France | Work done from a country other than France |
| For tax, one hour worked remotely counts as a whole day | Business trips in France ordered by your employer |
Up to 10 days a year of temporary assignments outside Switzerland can be counted within your 40%. Beyond those 10 days, the extra days are taxed in France, even if you stay under the 40% threshold.
What happens if you go over
- Under 40% remote work, but more than 10 days of assignments: the assignment days beyond 10 are taxed in France.
- Above 40% in total: Switzerland taxes up to the 40% limit, France taxes everything above it.
- Above the social security threshold that applies to you: you move to the French system, which affects your pension and your cover.
The two tax authorities exchange salary data automatically. So this is not something that goes unnoticed.
Keep your own count, day by day, in a simple table. If you are checked, the burden of proof is on you, not on your employer. A shared calendar signed off by your manager, or a signed remote-work policy, is worth far more than a memory.
And check once a year that your A1 certificate is still valid: it covers three years at most, and it can be applied for retroactively up to twelve months back.
What to do
-
Ask your employer whether they have applied for the A1 certificate
Your employer is the one who applies, to the competent office. Without it, your real ceiling is 25%, not 49.9%.
-
Set your pattern below the threshold
Two days a week is about 40%: you are right on the limit. One week of catching up and you are over. A pattern of a day and a half leaves you some room.
-
Write down every day
Date, place, and if you can, a record signed off by your employer. That document is what will protect you if you are checked, years later.
The three most common mistakes
- Thinking there is only one threshold. The 40% tax threshold and the 49.9% social security one are two different rules, and the lower one is the one that applies to you.
- Assuming the A1 has been applied for. Many employers never have, and the employee does not know until a check.
- Counting in weeks rather than over the year. The calculation is on the annual total: three weeks at a hundred per cent in December can tip the whole year over.
How many days do you have left this year, given your working hours and your assignments?
Heidi's cross-border mode does the count.
The questionnaire, the regime that applies, the thresholds and the deadlines are free. The figures — net pay, the full cascade, the cost of commuting — are in Heidi Plus.
Read next
- Retirement as a cross-border worker: AVS, the second pillar and the second right to choose
- Family allowances for cross-border workers: Switzerland or France?
- What happens to my second pillar when I leave my Swiss job?
- Unemployment as a cross-border worker: where to register, who pays and how much?
- G permit: conditions, going home and changing employer
- Quasi-resident status: who can apply, and by when?
- Who gets my taxes as a cross-border worker: France or Switzerland?
- How much do you take home in Switzerland as a cross-border worker?
- Cross-border workers: LAMal or French cover? The right to choose explained
- B, L or C permit: which one applies to me and how do I get it?
- How does the Swiss three-pillar pension system work?
Sources
- République et canton de Genève — Agreements applying to remote work by cross-border workers
- Frontaliers Grand Est — Tax and social security thresholds for cross-border remote work
- The 40% rule: working it out in days, what counts and what does not
Page written by the Heidi team and updated on 13 November 2026. The French-Swiss tax amendment has applied since 1st January 2026; between 2023 and 2025, a transitional agreement along similar lines was in force. The social security rules depend on your exact situation: the decision rests with the competent offices.