Tax Residency on Departure from Luxembourg 2026: Administration des Contributions Directes and Final Filing
Quick answer: Luxembourg considers you a tax resident if you have your tax domicile or habitual residence there. Effective departure means deregistering at the commune and notifying the Administration des Contributions Directes (ACD). The final tax return covers the move year. Luxembourg has tax treaties with more than 80 countries. MyGuichet handles tax filings from abroad.
Key takeaways
- Domicile or habitual residence = resident.
- Notify ACD on departure.
- Final return for move year.
- Treaties with 80+ countries.
- MyGuichet works from abroad.
What changes in 2026: ACD digital filing and split-year residence
The 2026 update to the loi modifiee du 4 decembre 1967 concernant l’impot sur le revenu (LIR) consolidates the digital filing channel run by the Administration des contributions directes (ACD). The MyGuichet.lu portal, signed with LuxTrust, is now the default route for the declaration de l’impot sur le revenu, and from tax year 2025 onwards an additional electronic split-year notification is integrated for taxpayers leaving the country mid-year. The ACD recognises a clean split between resident period (worldwide income taxable in Luxembourg up to the departure date) and non-resident period (only Luxembourg-source income taxable) – provided commune deregistration and supporting documents are filed.
Practically: residents who emigrate during the year remain unlimited tax residents (resident fiscal) up to the day before the certificat de radiation date; from the next day they become non-residents (non-resident fiscal) under article 156 LIR. This means a single tax filing covering both periods, with the worldwide-income period showing on form 100 and the Luxembourg-source-only period typically combined on the same return. Joint taxation of married couples (classe d’impot 2) follows the household, not the individual, so a partial-year departure can affect classe d’impot for both spouses.
Step-by-step: from departure to ACD final filing
1. Trigger the ACD upon commune deregistration. The commune transmits the change of residence to the RNPP automatically, but it is wise to upload the certificat de radiation directly to your ACD MyGuichet space within 30 days. Without this, the ACD may continue to assess unlimited tax liability.
2. Decide on the assimilation choice (article 157ter LIR). If your Luxembourg-source income represents at least 90% of your total worldwide income (or in some cases 50% under specific cross-border worker rules) you may opt to be assimilated to a resident taxpayer, preserving the full barema and credits for the Luxembourg-taxed period. This option is filed on form 163 R alongside the declaration de l’impot sur le revenu.
3. Obtain a Luxembourg attestation de residence fiscale for the resident period, requested via MyGuichet or in writing from the bureau d’imposition. This document is essential to claim the protection of double-tax treaties in your new country and to prove that you ceased Luxembourg residence on the departure date.
4. File the final declaration de l’impot sur le revenu for the year of departure between January and 31 March of the following year (extended automatically to 31 December when filed via MyGuichet). The ACD will issue a bulletin de l’impot sur le revenu (tax assessment) within 6-12 months. Pay any balance due via the displayed reference; refunds land on the IBAN registered with the ACD.
Special cases: cross-border workers, dual residence, retirees, EU staff
Cross-border workers becoming non-residents
If you keep a Luxembourg employer after the move, you become a frontalier whose Luxembourg-source salary remains taxable in Luxembourg under the relevant double-tax treaty (France 2018, Belgium 2017, Germany 2012). Withholding tax (retenue d’impot sur les traitements et salaires) continues to apply at the non-resident barema; the new country of residence applies its own rules to credit Luxembourg tax (exemption with progression for France/Belgium/Germany). The 50% Luxembourg-source rule under article 157ter LIR allows assimilation to a resident regime if conditions are met.
Dual residence and treaty tie-breaker rules
If both Luxembourg and the destination country claim residence for any part of the year, the treaty tie-breaker rules apply (typically permanent home, then centre of vital interests, then habitual abode, then nationality, then mutual agreement procedure). Document the move date by keeping the certificat de radiation, the new commune registration certificate abroad, the foreign rental contract or property deed, and a chronology of family movements.
Retirees moving abroad
Most CNAP pensions paid to non-residents are taxed only in the country of residence under the OECD Model Tax Convention article 18 – except ’public-service’ pensions (article 19) which generally remain taxable in Luxembourg. The CNAP applies the non-resident retenue d’impot unless an attestation de residence is filed. See our pension abroad guide.
EU and international officials
Staff of EU institutions in Luxembourg are not taxable on their salaries or emoluments in Luxembourg under Protocol 7 of the Treaty on the Functioning of the EU. Their tax residence for non-EU income remains the Member State they had before joining the institution (article 13 of the Protocol). On departure, the protocol may continue to apply or fall away depending on whether the new role still falls within the protocol scope.
Common pitfalls when changing tax residence
| Pitfall | Consequence | Prevention |
|---|---|---|
| Late filing of departure declaration | ACD assumes continued residence, full worldwide tax | Upload certificat de radiation within 30 days; file declaration before the next 31 March |
| Forgetting article 157ter assimilation | Loss of resident-style credits and barema for the move year | Tick the assimilation box on form 100 / 163 R if 90% (or 50%) Luxembourg income condition met |
| Not informing the new country’s tax authority | Risk of double taxation, missed treaty relief | Register with the new country’s tax office on arrival; bring attestation de residence Luxembourg |
| Selling property right after move | Loss of half-rate exemption (demi-taux global) on capital gain – see property sale guide | Plan sale BEFORE deregistration when feasible, or wait 2 years and qualify under main residence rules |
| Stock options or RSUs vesting post-move | Allocation between Luxembourg and new country complex, double tax risk | Document grant, vesting and exercise dates; seek tax advice; file form 100 with allocation table |
Withholding mechanisms (retenue a la source) after departure
Several Luxembourg-source incomes continue to be subject to retenue a la source after you become non-resident: salaries paid by a Luxembourg employer (retenue sur traitements et salaires), pensions paid by CNAP or supplementary pension funds (article 19 LIR cases), directors’ fees (tantiemes) at 20% under article 152 LIR, dividends from Luxembourg companies at 15% under article 146 LIR (often reducible by treaty), and certain Luxembourg-source interest covered by the European savings directive transposition. Each of these may be reclaimed in part by filing a non-resident return or claiming treaty relief.
The interaction between the Luxembourg retenue and the new country’s tax authority is treaty-specific. France/Belgium/Germany frontaliers benefit from clear allocation rules; for moves outside the EU it is critical to consult a tax adviser and review the relevant treaty article-by-article.
Timeline: ideal 12-month tax-residence change plan
Month -6: Estimate Luxembourg-source vs worldwide income; check whether 157ter assimilation will apply; review stock options vesting calendar.
Month -3: Notify employer of upcoming move and intended frontalier or non-frontalier status. Notify CNAP if drawing pension. Set up MyGuichet.lu access if not already done.
Month -1: Book commune appointment. Compile substance evidence for new country (rental contract, energy bill, school registrations).
Month 0 (departure): Receive certificat de radiation. Upload to ACD MyGuichet. Request attestation de residence fiscale for the resident period.
Month +1 to +3: Register with new country’s tax authority. Update bank tax-residence flags. File any quarterly cross-border worker declarations if applicable.
Month +6 to +9 (depending on next 31 March): Prepare and file the final Luxembourg declaration de l’impot sur le revenu via MyGuichet. Claim treaty relief on retenues.
Year +2: Receive the bulletin de l’impot sur le revenu for the year of departure. Pay any balance or receive refund. File any subsequent non-resident returns if Luxembourg-source income continues.
FAQ
When do you become non-resident?
After actually transferring domicile and habitual residence abroad.
Final return?
For the move year; covers income from the resident period.
MyGuichet useful?
Lets you submit returns and forms from abroad.
Luxembourg pension?
Taxed under the destination country’s treaty.
Frontier workers?
Specific non-resident regime for those still employed in Luxembourg.
When does my Luxembourg tax residency end?
On the day after your certificat de radiation date, in line with the commune deregistration. From that day, you are considered a non-resident for Luxembourg income tax (article 156 LIR), and only Luxembourg-source income is taxable. Up to and including the departure date, you remain unlimited tax resident on worldwide income.
Do I have to file a Luxembourg tax return for the year I leave?
Yes, in nearly all cases. The departure year requires a final declaration de l’impot sur le revenu covering the resident period (worldwide income) and the non-resident period (Luxembourg-source income). It is filed via MyGuichet.lu by 31 March of the following year (deadline extended to 31 December for online filings).
What is article 157ter LIR assimilation and should I opt for it?
Article 157ter allows non-residents whose Luxembourg-source income is at least 90% of worldwide income (or 50% in specific cross-border worker cases) to be assimilated to residents for tax purposes. This usually preserves the full barema, joint taxation, and most credits. It is opted for on form 163 R and decided year by year.
Will Luxembourg tax my foreign salary or rental income after I move?
No. Once you are non-resident, only Luxembourg-source income (Luxembourg salary, Luxembourg pensions, Luxembourg-located real estate, certain Luxembourg dividends) is taxable in Luxembourg. Foreign salary, foreign rentals, and foreign investment income are taxed by the new country of residence under the relevant double-tax treaty.
Document your move with employment or rental contract in the destination country.
Flyto Relocation handles your international move from Luxembourg. Get a free quote.
See also: All Luxembourg moving guides.