Address

• What address should I indicate in the "Where do you live now?" fields ?

  In the "Where do you live now?" fields, indicate the address at which you currently live, i.e. at the time of filling in your tax return. If you have changed your address in 2025, you must press the "Add an address" button and insert your old address.Few readers

• What should I do if I have had several addresses during the year?

  If you have had several addresses during the year, it is important to mention this. In this case you can attach a document in which you explain in detail the changes of address during the year, specifying the different dates of occupation.Few readers

• What should I do if I have had several addresses during a tax year?

  On taxx.lu, in the ‘Personal data’ section, you can enter your current address as well as a previous address. If you have moved several times during the tax year, please create a document (for example, a Word file to be converted into a PDF or a PNG image) summarising all your addresses and the respective periods of occupation for the year in question. Once the document has been created, simply import it under ‘Other appendices’ in the ‘Attachments’ section. ![](https://storage.crisp.chat/usFew readers

Civil status

• Do I need to complete a tax return as a single person?

  It depends on your circumstances: your income, the number of employers you have, income from several countries, etc. In some cases, filing a tax return is compulsory; in others, it is optional but may enable you to claim a refund of overpaid tax.Few readers

• What is my tax class after a divorce?

  For the three tax years following the year in which you ceased to live together, you may, subject to certain conditions, be eligible for tax class 2 (without being taxed jointly with your former spouse). At the end of this transitional period, you will be placed in tax class 1 if you have no dependent children in your household, or in tax class 1a if you have one or more dependent children.Few readers

• Who should sign the tax return if my spouse has died during the year?

  As the surviving spouse, you are the one who should sign the tax return. If probate proceedings are underway, the tax authorities may ask you to provide certain administrative documents (such as a certificate of inheritance), depending on the circumstances.Few readers

• Do I need to file a tax return for the year in which my spouse died?

  Yes, in principle, a joint tax return is still required for the year of death, including your spouse’s income up to the date of their death and your own income for the whole year.Few readers

• What is my tax class if I become a widower or widow?

  Subject to certain conditions, you will remain in tax class 2 for the three tax years following the death of your spouse or partner. At the end of this transitional period, you will normally be placed in tax class 1a, which is more favourable than class 1, applicable to single people without children.Few readers

• What is my tax class if I am single?

  If you are not married or in a civil partnership and do not have any dependent children, you will generally fall into tax bracket 1. This tax class also applies if you are pacs, as pacs does not affect your tax class in Luxembourg.Few readers

• Does living with a partner affect my tax return?

  No. In Luxembourg, living with a partner does not result in a joint tax return or a change in tax bracket. Each partner continues to declare their income separately, except in the case of marriage or a civil partnership (PACS).Few readers

Tax identification number (NIF)

• Where can I find my Belgian tax identification number (TIN)?

  The tax number can be found on the following documents: On the back of your Belgian identity card On the back of your Belgian social security card On the back of your residence permit and vehicle registration certificate for foreigners residing in BelgiumPopular

• Where can I find my tax identification number (tax ID / TIN)?

  Most EU Member States use Tax Identification Numbers (Tax ID) to identify taxpayers and simplify the administration of your national tax obligations. Here is a guide to help you find your tax identification number: For Luxembourg : The file number is assigned by the Tax Administration and does not change from one year to the next. You can find it on every correspondence from the Tax Administration (e.g., last year's tax statement) This is a 9 or 11-digit number. ![](https://storage.crPopular

• Where can I find my French tax identification number (NIF)?

  The tax number can be found on the following documents: on your pre-filled French tax return, top left of the first page, with the online access number on your French tax notices (income tax, secondary residence tax, property tax) top left, under the heading ‘Your references’.Popular

• Where can I find my tax identification number (TIN)? (Countries that do not border Luxembourg)

  The tax identification number (TIN) in countries that do not border Luxembourg can generally be found on the following documents, depending on the country: Spain: The Spanish NIF can usually be found on the ‘NIE’ (Identification number for foreigners), which may appear on official documents such as your foreigner's identity card or residence certificate. Italy: The Italian NIF, called Codice Fiscale, appears on various documents such as the electronic identity card, tax returPopular

• Where can I find my German tax identification number (TIN)?

  The tax number can be found on the following documents: On your German tax notice:Few readers

File number (assigned by the ACD)

• Where can I find my Luxembourg file number (NIF)?

  The file number is assigned by the Tax Administration and does not change from one year to the next. You can find it on every correspondence from the Tax Administration (e.g., last year's tax statement) This is a 9 or 11-digit number. If it is your first tax return, you will not have this number yet. In that case, leave the field blank.Some readers

• Where do I enter my Luxembourg tax file number?

  The file number (if allocated) must be indicated in the ‘’Other‘’ category!Few readers

• What if I don't have a Luxembourg telephone number?

  If you do not have a Luxembourg telephone number, you can still enter your foreign number by adding the prefix.Few readers

• What should I do if I do not have a Luxembourg identification number?

  If you do not have a Luxembourg registration number, leave the box empty.Few readers