Most Luxembourg citizens and cross-border workers must complete a tax declaration in Luxembourg every year. The declaration gives you the opportunity to deduct various expenses and so reduce the amount of tax. Although Luxembourg has the reputation of being less complicated than its neighbours, there are always some queries. In this article, we’ll take a look at the main rules to follow.

Luxembourg tax return: dates and timescales
In Luxembourg, you make your tax return before the 31 December, for income for the preceding year.
The tax authorities send out a withholding tax card (fiche de retenue d’impôt) during January or early February. This document is sent to your employer and allows it to deduct tax at source from your salary.
The formats and how to fill in the form
The paper version (form 100F for French speakers) is still used, but is gradually being replaced by electronic exchanges.
If you go online , you have two options: you can
- Download and fill in a PDF version of the 100 form, then send it back via MyGuichet.lu.
- Fill in your form directly at the portal MyGuichet.lu.
In both cases, you need to login using a LuxTrust certificate, to guarantee maximum security.
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Points to watch
You can claim a certain number of deductible expenses. Some examples are:
- Necessary costs (expenses related to carrying out a salaried activity)
- Pensions paid to a divorced spouse, maintenance payments and other standing payments
- Compulsory social-security contributions and deductions
- Insurance contributions and premiums
- Premiums paid into a protect4life personal protection insurance (deduct up to €672 a year)
- Contributions into an additional pension plan (deduct up to €3,200 a year), gifts and largesse, etc.
- Mortgage insurance premium (deduct up to €672 a year)
- Premiums paid into a homebuyer savings plan
- Costs of domestic services and child care
The tax advantages of insurance products
For many taxpayers, life-assurance and pension products remain the best ways of benefitting from a series of ceilings for deductible expenses.
Insurance products in fact offer two tax advantages
- The premiums are deductible
- The capital value on maturity is exempt from income tax, except for pension products
Which banking and insurance products are tax deductible?
- Home and car third-party liability insurance
- Additional mutual health insurance
- Interest charges on a personal loan
- Life insurance *
- Pension savings **
- Death insurance
- Loan insurance
- Children’s savings plans *
- Homebuyer savings plan
* To benefit from the tax advantages provided in Luxembourg law, life insurance policies with a savings element must have a minimum term of 10 years.
** 2 conditions: minimum contract term of 10 years and retirement age between at least 60 and 75.
Cross-border worker
If you are a French or Belgian cross-border worker and want specific information about your obligations or possible deductions, please refer to the tax guide. (https://www.guidedesimpots.lu).