Cross-border workers: being treated like a resident
This guide is for people who live in France, Belgium or Germany and work in Luxembourg. It explains the option to be treated like a resident, and why it is worth comparing both ways.
The default for non-residents
As a non-resident you get few deductions by default: minimum flat amounts, compulsory social contributions and some pension contributions. For example, loan interest is not deductible.
The option: treated like a resident
On form 100 you can ask to be treated like a resident (assimilation, article 157ter of the income tax law). The resident deductions and credits then apply to you.
Do you qualify?
You qualify if one of these applies: at least 90% of your worldwide professional income is taxable in Luxembourg (days worked outside Luxembourg count as Luxembourg-taxable up to 50 days); or the income that is not taxed in Luxembourg is under €13,000 net; or, for Belgian residents only, more than 50% of your household's professional income is taxable in Luxembourg.
Compare before you choose
Once you are treated like a resident, your foreign income can raise the rate applied to your Luxembourg income. It is therefore worth comparing both ways. For couples, both spouses sign the request.
Tax class
Married non-residents are in class 1, unless they are treated like residents and taxed jointly, in which case they are in class 2. Class 1a (for example with a child who gives a tax reduction, or from age 64) is possible either way.
Deadline and a note on 2025
The deadline for tax year 2025 is 31 December 2026. For 2025 the tax scale was indexed by 2.5 brackets.
How we help
We compare both ways for you, prepare the return and, with the Premium package, file it.
Checked on 8 Oct 2026 for tax year 2025
General information from official sources, not tax advice. Your situation can differ. We check everything when we prepare your return.
Official sources
- ACD: FAQ for non-residents(opens in a new tab) (page updated 5 Oct 2026)
- ACD: form 100F 2025(opens in a new tab)
- gouvernement.lu: what changes in 2025(opens in a new tab) (page updated 27 Dec 2024)