Specialist legal portal Service-Juridique published a comprehensive reminder of the fiscal framework governing cross-border telework between Switzerland and France. The article, dated 18 September 2026, explains the practical application of the additional protocol to the 1966 Double-Taxation Convention, in force since 1 January 2026. Key takeaway: as long as a French-resident employee spends no more than 40 % of annual working days teleworking from France—and mission trips count only up to 10 days—the entire salary remains taxable in Switzerland. Exceeding the 40 % or 10-day caps triggers French taxation on the excess days and may strip the employee of ‘frontalier’ status under the 1983 agreement. Employers face new compliance duties. By 30 November each year, they must transmit to cantonal tax authorities detailed attestations showing each cross-border worker’s telework percentage. Cantons will then supply the data to French tax authorities under the automatic salary-data exchange mechanism beginning in 2027. HR departments must therefore enhance time-tracking systems and educate managers to avoid inadvertent threshold breaches that could generate double taxation and payroll corrections. For mobility and assignment managers, the clarified rules offer welcome certainty after a series of pandemic-era interim accords. The 40 % allowance provides flexibility to retain hybrid-work models while keeping payroll in Switzerland, but only if mission days and part-time schedules are monitored meticulously. Companies with sales teams or engineers frequently dispatched abroad should review travel-calendar projections now to stay within limits. Failure to comply could expose firms to back-tax assessments in France and penalties for late reporting. Multinationals should also watch for parallel negotiations with Germany and Italy, where similar telework debates are gaining momentum.
Source: Service-Juridique
