Cross-border telework between France and Switzerland: how many home-working days keep your tax and social security unchanged

You can work from home in France for up to 40 % of your working time over the calendar year without changing the country that taxes your salary. For a full-time job, that is roughly two days a week out of five, kept up all year. The rule comes from the amendment of 27 June 2023 to the France-Switzerland tax treaty (avenant à la convention fiscale), in force since 24 July 2025 and applying from 1 January 2026. Business trips (missions temporaires) in France or a third country count inside the 40 %, up to 10 days a year.

What follows depends on your employer’s canton. In Geneva and in cantons outside the 1983 agreement (Zurich, Fribourg, Ticino...), the whole salary stays taxed in Switzerland up to 40 %. In the eight cantons of the agreement of 11 April 1983 (Bern, Solothurn, Basel-Stadt, Basel-Landschaft, Vaud, Valais, Neuchâtel, Jura), the salary is taxed in France, and the mutual agreement of 22 December 2022 (accord amiable) keeps the cross-border regime within the same 40 % limit. According to OCSTAT, 414 262 cross-border workers (frontaliers) worked in Switzerland in the second quarter of 2026.

Above 40 % telework over the calendar year, the allowance no longer applies. With an employer in Geneva or in a canton outside the 1983 agreement, the part of your salary that matches your home-working days becomes taxable in France from the first day, not only for the days above 40 %. The part linked to days worked in Switzerland stays subject to Swiss withholding tax (impôt à la source). The employer can reduce the income subject to withholding tax by the part taxable in France.

For the 1983 cantons, the 2022 mutual agreement only guarantees the cross-border regime up to 40 %: above that, have your situation checked before the year in question.

Going over will not go unnoticed. Under the amendment, the employer’s country sends the country of residence, each year and by 30 November of the following year, the number of telework days or the telework percentage of each employee. AFC Genève also warns that frequent telework can create a permanent establishment of the employer in France.

Yes, your Swiss employer can refuse telework or set a cap below 40 %: the threshold is a tax rule, not a right to work from home. The amendment only covers telework done under the contractual terms agreed between employee and employer. Under Swiss law, the employer may issue general instructions on how work is performed (article 321d of the Swiss Code of Obligations).

Many employers set a lower cap to keep a margin for business trips, irregular weeks and the risk of a permanent establishment in France. If your contract is governed by French law, article L1222-9 of the French Labour Code requires the employer to give reasons for refusing telework when the post is eligible under the collective agreement or the company charter. Ask for a written amendment to your contract that sets the number of days and the counting method.