Personal taxation · Luxembourg
How to amend a tax return in Luxembourg
How you correct a return depends on the status of your file. Before the tax assessment notice, send a written request with supporting documents to the competent tax office. Once a decision has been notified, also check the objection route and deadline: a new version of the form is not always enough.
Financial Services Luxembourg · Licensed accountant · Head of the firm: Mickaël LOC. Editorial update: .
Place the error in the timeline
| Stage | What to prepare | Point to watch |
|---|---|---|
| Draft not yet sent | Corrected version and documents | Correct it before submitting |
| Return sent, no tax assessment notice | Written request, file reference, justified correction | Guichet.lu refers to a request within three months of sending |
| Tax assessment notice received | Notice, return, notification and documents | Check the objection deadline for the decision |
| Deadline possibly missed | Complete timeline | Have the remaining options checked, with no assured outcome |
Make the correction easy to follow
State the year, the section concerned, the original amount and the proposed amount with the corresponding supporting document. Keep a copy of what you send and explain the expected effect. A complete file helps distinguish a data entry error from a question of tax classification.
Fictitious example: a corrected certificate replaces the one used when filing. You need to identify the replaced document and its impact on income and withholding tax, without adding the two versions together.
After the tax assessment notice
A request for adjustment sent to the tax office and an objection to the Director of the Luxembourg Inland Revenue (ACD) have different functions and conditions. Do not assume that a phone call or an email exchange preserves an appeal deadline.
The date of notification, the addressee and the subject of the challenge must be checked on the document itself. Payment and collection remain a separate question; challenging a decision does not automatically allow you to stop paying.
Useful documents
- The return actually sent and proof of filing.
- The tax assessment notice and envelope or notification details, if any.
- The original supporting document, the corrected document and an explanation of the difference.
- Letters already exchanged with the ACD.
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
- Guichet.lu: tax return, filing and correction
- Guichet.lu: challenging an ACD decision
- ACD: questions from resident taxpayers
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.