Cross-border guide · France
France–Luxembourg cross-border workers: home office and the 34-day rule
You live in France and work in Luxembourg? Here is how many days you may work outside Luxembourg, what happens on day 35 and how to keep count.
127,772 cross-border workers live in France and work in Luxembourg. Sources: STATEC, figures of 12 October 2026 · Luxemburger Wort, October 2026 · Chambre des Députés, file 8121.
The 34-day rule
How much of your salary flips on day 35?
Beyond 34 days it is not just the extra days: every day worked outside Luxembourg becomes taxable in the country of residence, from the very first. The salary is then split pro rata to the days worked in each country.
Home office, business trips and training outside Luxembourg count; a day started counts as a full day. The amount of tax depends on the rates in the country of residence and the household situation; Luxembourg tax falls accordingly. General information, not tax advice.
Above the threshold: what changes
France
- The Luxembourg employer does not withhold French tax: the employee pays monthly instalments, on the 15th of each month.
- The employer registers in France (PASRAU, SIRET number) and files monthly on net-entreprises.fr, by the 10th at the latest.
- Up to 50 days in France, the employee is still treated as a resident for the Luxembourg 90 % rule.
Sources: Frontaliers Grand Est — France
Keep count, day by day
Log your days in “My counter”: free, no account, installable on your phone.
Open my counterWorking in HR?
homeoffice.lu tracks the days of all your cross-border staff and warns before day 35. Free 30-day trial.
See the business offerFrequently asked questions
How many home office days may a cross-border worker living in France work?
For tax, 34 days a year outside Luxembourg — home office, business trips and training combined. For social security, up to 49.9 % of working time in home office. The two rules are counted separately.
What happens on day 35?
Beyond 34 days it is not just the extra days: every day worked outside Luxembourg becomes taxable in the country of residence, from the very first. The salary is then split pro rata to the days worked in each country.
Which days count?
Home office, business trips and training outside Luxembourg count; a day started counts in full.
What must the employer do if the threshold is exceeded?
The Luxembourg employer does not withhold French tax: the employee pays monthly instalments, on the 15th of each month. The employer registers in France (PASRAU, SIRET number) and files monthly on net-entreprises.fr, by the 10th at the latest. Up to 50 days in France, the employee is still treated as a resident for the Luxembourg 90 % rule.
General information, not tax advice. Check your situation with the tax authority or an adviser.