Cross-border teleworking: the 34-day rule
Skimming?
We've prepared the shortcut for you.
The threshold is the same in all three countries, but the counting method differs: in France, it is reduced for part-time work or mid-year hires; in Germany, an activity lasting under 30 minutes does not count. Training sessions and business trips count towards the limit. At trigger, we advise keeping a calendar starting in January: one day too many can be costly. Social security follows a different rule based on percentage of working time.
This is for you if
- You live in France, Belgium, or Germany and work for a Luxembourg employer.
- You work remotely, attend training courses, or go on business trips outside Luxembourg.
Not for you if you are a public employee paid by the Luxembourg State: specific rules apply depending on your nationality and country of residence (ACD non-residents FAQ (ouvre dans un nouvel onglet)).
Key figures
| Rule | France | Belgium | Germany |
|---|---|---|---|
| Annual threshold | 34 days, since 2023 (29 before) | 34 days, since 2022 (24 before) | 34 days, since 2024 (19 before) |
| Partial day | Counts as 1 day | Counts as 1 day | Counts as of 30 minutes of work outside Luxembourg |
| Part-time or mid-year arrival | Threshold reduced pro rata, rounded down to the nearest whole number (2020 mutual agreement, reaffirmed by the June 2026 circular) | No reduction (2023 ACD details) | No reduction (2024 circular) |
| Beyond the threshold | Taxable in France from the 1st day outside Luxembourg | Taxable in Belgium from the 1st day | Taxable in Germany from the 1st day, pro rata to working time |
| Reference text | ACD Circular No. 61 of 24 June 2026 | ACD details of 2 March 2023 | ACD Circular No. 71 of 18 March 2024 |
What counts as a day
The criterion is your physical presence outside Luxembourg for work purposes. The following count: working remotely from home, training sessions, and business trips, whether in your residence country or a third country (ACD FAQ (ouvre dans un nouvel onglet)). In France and Belgium, spending a morning working at home and the afternoon at the office counts as a full day toward the 34-day limit. In France, however, when splitting your salary between the two countries, this half-day only counts as ½ day (ACD Circular No. 61).
According to ACD Circular No. 61 (France), the following do not count: leave, unworked weekends and public holidays, sick leave, and cases of force majeure.
Beyond the threshold, days spent in a third country are in principle taxable in your country of residence, unless the tax treaty between your residence country and that third country provides otherwise.
What about social security?
The 34 days only apply to taxation. Your coverage depends on a separate rule based on a percentage of your working time: under 25% in your country of residence, standard European rules apply; between 25% and under 50%, the European framework agreement in force since 1 July 2023 keeps you covered in Luxembourg if your country signed it and if your employer declares it to the Joint Social Security Centre (CCSS) (Luxembourg government (ouvre dans un nouvel onglet)).
How to count and manage your days
Keep a calendar starting 1 January
Log every day worked outside Luxembourg, even partially, including the location and reason (teleworking, training, mission).
Calculate your actual threshold
Cross-border worker in France working part-time or hired mid-year? ACD Circular No. 61 reduces the threshold: 34 × 75% = 25.5, rounded down to 25 days for a 75% part-time schedule; 34 × 6/12 = 17 days for a start date on 1 July. In Belgium and Germany, it is 34 days in all cases.
Keep proof
It is up to you to prove your physical presence: contract or employer statement, time sheets, tickets, hotel invoices, travel orders (ACD Circular No. 61).
If you exceed the limit, inform your employer
The ACD describes how to adjust the wage tax withholding (RTS) when working in Luxembourg and abroad (ACD Teleworking page (ouvre dans un nouvel onglet)). The taxable portion in your home country is reported there (in France, in boxes 1AG to 1DG: read declaring in your residence country). For questions about your tax card (the ACD document indicating your tax class to your employer), contact the RTS Non-residents office (find your office).
Check your tax treatment assimilation
For the 90% threshold for tax assimilation, up to 50 days taxed in your home country still count as Luxembourgish (ACD).
A practical example
Let's take Claire, who lives in Thionville: €60,000 salary for 220 working days, or about €272.73 per day. In 2025, she:
- teleworked 28 days from home;
- attended 5 days of training in Metz;
- worked 2 mornings from home before going to the office in the afternoon.
Day count: 28 + 5 + 2 = 35 days, with half-days counting as full days. The 34-day threshold is exceeded.
Taxable portion in France: ACD Circular No. 61 counts half-days as half a day for split calculations, i.e., 28 + 5 + 1 = 34 days. 34 × €272.73 = approx. €9,273 taxable in France, and approx. €50,727 in Luxembourg.
If Claire had cancelled just one morning at home, her count would have remained at 34: her entire €60,000 would have been fully taxable in Luxembourg. Simplified trigger calculation: salary is allocated pro rata based on days.
Common mistakes
- Only counting telework: training sessions and business trips outside Luxembourg also count toward the threshold (ACD).
- Believing that beyond the threshold, only the excess days are taxed in your home country: it applies from day one.
- Forgetting the pro-rata adjustment in France when working part-time or starting mid-year.
- Confusing the 34 days (tax) with the rule of 25% to under 50% (social security).
Frequently asked questions
No. Beyond 34 days, your country of residence taxes all days worked outside Luxembourg, right from the first day (ACD Circular No. 61 for France, ACD details for Belgium, Circular No. 71 for Germany).
No. Only days where you actually work outside Luxembourg count. Paid leave, unworked public holidays, and sick leave are excluded.
If you live in France, yes: 34 × 80% = 27.2, rounded down to 27 days (rounding down rule from Circular No. 61). In Belgium and Germany, no: you keep 34 days.
No. Social security operates on a percentage of working time (25% to under 50%), with its own procedures through the CCSS.