What documents do you need for your Luxembourg tax return?

Complete checklist of required documents for your Luxembourg tax return: salary certificates, insurance, deductions & more. Essential 2025 guide.

Every year, filing your tax return can seem daunting, especially when it comes to gathering all the necessary supporting documents. However, with a little organisation and the right checklist, you can save valuable time and avoid oversights.

In this article, we review the main documents you need to collect to correctly complete your tax return, and where to obtain them.

1. Income documentation

This is the foundation of any tax return: declaring all income received during the year.

• Annual salary certificate: Provided directly by your employer (usually between January and February).
• Allowance certificates (sickness, maternity, unemployment, etc.): Available on MyGuichet.lu or from CNS, ADEM, or the relevant organisation.
• Pension certificates (CNAP, FNS, etc.): Accessible on MyGuichet.lu or sent automatically by mail.
• Foreign income: Certificates issued by your foreign employer or pension organisation.

2. Deductions and special expenses

To reduce your taxable base, you can deduct certain expenses, provided you have the proper documentation:

• Insurance (liability, health, supplementary health, life, accident, etc.): Certificates sent annually by your insurer.
• Retirement savings (111bis contracts, supplementary pensions): Certificate provided by the insurer or financial institution.
• Home scheme savings: Certificate to request from your specialised organisation (BHW, Schwäbisch Hall, Wüstenrot, etc.).
• Interest on loans (mortgage or personal): Tax document provided by your bank.
• Donations to approved associations: Receipts issued automatically after donation.
• Childcare expenses: Invoices or certificates from daycare, childcare center, or childminder.
• Domestic help: Certificate from a service company or CCSS certificate if you directly employ the person.
• Alimony payments: Court judgment or agreement + proof of payment (bank statements).

3. Specific or exceptional Income

If you receive other types of income, you must also provide documentation:

• Rental income: Certificates from management agency or self-prepared documents (rental contracts, rent receipts, expense invoices, etc.).
• Investment income (interest, dividends, capital gains): Statements provided by your bank or brokerage platform.

Summary

Filing taxes in Luxembourg requires gathering documents related to your income, deductible expenses, and investments. The more you plan ahead, the simpler and faster the process will be.