Personal taxation · Luxembourg
Non-resident tax assimilation in Luxembourg: conditions
Assimilation to resident taxpayers allows a non-resident who meets the conditions to access, on request, provisions that apply to residents. It is assessed every year. The right to request assimilation and its financial benefit are two separate checks, because foreign income can change the Luxembourg tax rate.
Financial Services Luxembourg · Licensed accountant · Head of the firm: Mickaël LOC. Editorial update: .
The routes to tell apart
The general test looks at the share of worldwide income taxable in Luxembourg and is assessed individually for each spouse or partner. Another route concerns net income not subject to Luxembourg tax below EUR 13,000. The conditions are alternatives: they must not be added together as if all of them were required.
| Route | Reference condition | Point to watch |
|---|---|---|
| General rule | At least 90% of worldwide income taxable in Luxembourg | Annual and individual test, tax classification of the income |
| Foreign income route | Net income not subject to Luxembourg tax below EUR 13,000 | Strict threshold and relevant net figures |
| Belgian specific rule | More than 50% of the household's professional income taxable in Luxembourg | Reserved for Belgian residents; different household basis |
Why gross salary is not enough
The calculation is not a matter of dividing the employer's transfers by the receipts on your bank account. You must classify the income, determine its taxable amount and identify which country has the right to tax it. Rental income, pensions or investment income can change the analysis.
For the 90% test, a specific rule may treat as income taxable in Luxembourg certain employment income allocated abroad under a tax treaty, up to the limit corresponding to 50 working days. This assimilation mechanism does not change where those days are actually taxed.
Three fictitious examples of reading the conditions
First case: on tax bases assumed to be correct, EUR 54,000 is taxable in Luxembourg and EUR 6,000 abroad. The share reaches 90%. You still need to check the classification of the amounts and the request.
Second case: EUR 40,000 is taxable in Luxembourg and EUR 12,500 net is not. The proportional test does not reach 90%, but the route below EUR 13,000 deserves examination. These two tests are not cumulative.
Third case: a Belgian resident does not meet these individual tests, but more than half of the household's professional income is taxable in Luxembourg. The Belgian treaty route must be examined separately. None of these examples quantifies a tax benefit.
Eligible does not mean better off
Foreign income is taken into account to set the rate applicable to the domestic income taxable in Luxembourg under the assimilation mechanism. Access to deductions may be offset by this rate effect.
The comparison must use the same year, the same income and the same documents in each relevant scenario. For a couple, the taxation method requires an additional review.
Documents and request
Prepare the Luxembourg and foreign certificates, the other relevant income and the days worked outside Luxembourg. The request is made within Form 100, following the required sections and signatures.
A change of residence, exceptional income or an uncertain classification requires a review of the file. This page does not issue a certificate of eligibility.
The firm’s other tax engagements
Depending on your situation, the firm also handles tax, VAT and payroll, the regularisation of late tax filings and assistance during a tax audit. Fees are listed in the firm’s fee grid.
Official sources and scope
- ACD: assimilation to residents, article 157ter
- ACD: questions from non-resident taxpayers
- ACD: assessment based on a tax return
The rules apply to the year and profile concerned. Examples flagged as fictitious explain a method; they are not an individual validation. The documents and options of your file are covered by a separate engagement.