Swiss Cross-Border Workers: New Tax Rules Effective from 2025

Summary: Numerous changes are impacting cross-border workers between France and Switzerland in 2025. This article reviews the new double taxation rules, potential tax deductions, and strategic choices between the LAMal or CMU regimes. An essential guide to optimize your tax situation in full compliance.

Context: An Evolving Cross-Border Tax System

Each year, thousands of French citizens cross the border to work in Switzerland. Their tax situation is regularly discussed between the two countries. Since 2025, new rules have come into effect, profoundly changing how cross-border incomes are taxed and declared.

Double Taxation: What’s New in 2025?

Until 2024, cross-border workers were subject to bilateral agreements aimed at avoiding double taxation, with withholding tax in Switzerland and adjustment in France. Since 2025, the main changes are:

• Strengthened Information Sharing: French and Swiss tax authorities now automatically share more data, reducing the risk of omissions or errors.
• New Allocation Key: The 2025 agreement introduces a different tax allocation: Switzerland withholds tax at source, then France applies a tax credit equal to the amount paid in Switzerland.
• Harmonization of Thresholds: Certain income and deduction thresholds have been harmonized, limiting disparities depending on Swiss cantons.

Consequence: Declaring Swiss income in France remains mandatory, but the tax calculation method has changed. Personalized support can be valuable to avoid mistakes and optimize your taxes.

Deductions and Tax Optimization

Cross-border workers can benefit from several mechanisms to reduce their tax burden:

• Professional Expense Deductions: Commuting costs, temporary accommodation, or dual residence remain deductible, subject to conditions and annual limits.
• Health Insurance Deductions: LAMal or CMU contributions can be partially deducted from taxable income in France, depending on the household’s situation.
• Pension Savings Deductions: Payments into retirement savings products (like PER) remain deductible up to a certain limit, allowing for tax optimization while preparing for the future.

It is advisable to keep all supporting documents and check annual caps to avoid reassessment risks.

LAMal or CMU: Choosing the Right Health Insurance Scheme

The right of option between LAMal (Swiss health insurance) and CMU (French health insurance) still exists in 2025, but some adjustments should be noted:

• Reduced Decision Period: The period to exercise the right of option after starting work in Switzerland has been reduced to 3 months.
• Return Conditions: In the event of returning to France, re-enrollment in the CMU is facilitated under certain conditions.
• Tax Impact: Contribution rates and deduction methods differ according to the chosen regime. A personalized audit is recommended before making any decision.

The choice between LAMal and CMU affects both health coverage and taxes. A comparative simulation helps identify the most suitable solution for each situation.

Practical Tips to Optimize Your Tax Situation

• Prepare Your Return in Advance: Don’t wait until the last minute to prepare your tax return. The new requirements demand increased attention to collecting Swiss and French documents.
• Consult a Specialist: A cross-border tax expert will identify optimization strategies tailored to your profile.
• Use Official Simulators: Government agencies offer online tools to estimate the tax due and assess the impact of different tax options.

Conclusion

2025 marks a turning point for the taxation of Swiss cross-border workers. With a new tax allocation, adjustments to deductions, and changes to the right of option, it is essential to stay informed and seek guidance to remain compliant while optimizing your situation. Feel free to consult our other articles or contact our advisors for personalized support.