Luxembourg Cross-Border Workers: Tax Guide for France, Belgium and Germany

Taxation rules by country of residence

In principle, cross-border workers are taxed in Luxembourg on their Luxembourg employment income, and their country of residence grants a tax credit or exemption to avoid double taxation. Since 2024, French cross-border workers have benefited from an expanded remote-work tolerance (34 days). Belgian cross-border workers have 34 days of tolerance since the 2023 amendment. German cross-border workers are also subject to a 34-day threshold, above which days worked from Germany are taxed in Germany.

Filing obligations

• Luxembourg tax return (form 100) required if Luxembourg income exceeds 90% of worldwide income or optional for optimisation
• Tax return in the country of residence including Luxembourg income (with tax credit or exemption method)
• Residence certificate to be obtained in the country of residence for withholding purposes
• Tax withholding card (RTS) issued by the Luxembourg Administration des Contributions Directes

Optimisation for cross-border workers

Cross-border workers can optimise their situation by requesting tax assimilation to Luxembourg residents (if more than 90% of their income comes from Luxembourg), which gives access to Luxembourg tax deductions: mortgage interest, retirement savings contributions, special expenses. The impact can represent savings of 1,000 to 5,000 euros per year depending on family situation. It is crucial to compare the regimes of both countries to choose the most advantageous option.