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Employees · My situation

Cross-border worker: living in Belgium, working in Luxembourg, France, the Netherlands or Germany

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Where is my salary taxed and insured?

Your salary is taxed in the country where you physically work. Every working day in Belgium, teleworking included, is therefore taxable in Belgium, except for Luxembourg, which allows 34 days a year outside its territory. Foreign salary is exempt in Belgium, but it counts for the rate of your Belgian tax and, except for Luxembourg, for your municipal tax.

For social security, you remain insured in your employer’s country as long as you work less than 25% of your time in Belgium, or less than 50% teleworking with your employer’s agreement. This page covers the Belgian side: it does not calculate foreign tax.

34 daysa year outside Luxembourg with no Belgian tax, since 2022
0 daysof tolerance with France, the Netherlands and Germany
25%of working time in Belgium: social security switches, unless teleworking is below 50%

Where is your salary taxed?

The tax treaties between Belgium and its neighbours follow the same rule: salary is taxable in the country where the work is done. What counts is not the employer’s country, but where you physically are that day. A day teleworking at home, a day of meetings in Brussels: taxable in Belgium.

Country of workDays in Belgium toleratedBelgian municipal tax on the salaryTreaty applied
Luxembourg34 days a year outside Luxembourg (Belgium and third countries)No1970 treaty, 2021 protocol
FranceNone: every day in Belgium is taxable in BelgiumYes1964 treaty (the 2021 one is not in force)
NetherlandsNone: every day in Belgium is taxable in BelgiumYes2001 treaty (the 2023 one is not in force)
GermanyNone: every day in Belgium is taxable in BelgiumYes1967 treaty, 2002 protocol
Belgian resident employed by a foreign employer, rules in force on 18 October 2026. Sources at the bottom of the page.

The old cross-border regimes, which allowed the salary to be taxed in Belgium, no longer exist for Belgian residents: since 2007 income for France, and since the 2002 protocol for Germany. The Franco-Belgian cross-border regime that remains until 2033 only covers residents of France who work in Belgium.

Luxembourg: the 34-day rule

You can work up to 34 working days a year outside Luxembourg, in Belgium or another country, without Belgium taxing those days. All your salary then remains taxable in Luxembourg.

  • Part of a day counts as a whole day.
  • The threshold is the same if you work part-time or only part of the year.
  • Above 34 days, Belgium taxes all the days worked in Belgium, from the first one. With 40 days in Belgium out of 220, that makes 18% of the salary.

The tolerance was 24 days from 2015 to 2021. Luxembourg salary is not subject to Belgian municipal tax: the treaty does not allow it, and Luxembourg pays a lump sum to Belgian municipalities instead.

France, the Netherlands, Germany: no tolerance

With these three countries, no days working from home are tolerated. The salary is split in proportion to working days: 44 days working from home out of 220 means 20% of the salary is taxable in Belgium, and 80% in the employer’s country. Plan for Belgian tax on those days: if it is not withheld every month, you will be asked to pay it after your tax return.

Negotiations are under way, but nothing is in force as of 18 October 2026: the new treaty with France (2021) has not been ratified, the one with the Netherlands (2023) would only apply in 2027 at the earliest and contains no teleworking rule, and the texts with Germany have not been published. With Germany, to offset the Belgian municipal tax, the German tax on your salary is reduced by 8%.

Where is my salary taxed and insured?

Enter your employer’s country and your working days in Belgium. Indexo applies the rule of the treaty and of the EU regulation, on the Belgian side.

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Foreign salary in your Belgian tax return

As a resident of Belgium, you declare all your income in Belgium, including salary taxed abroad. It is exempt, but under the ‘exemption with progression’ rule (réserve de progressivité): Belgian tax is calculated on all your income, then reduced in proportion to the exempt part. Your Belgian income, or your spouse’s, is therefore taxed at the rate it would have with your foreign salary.

The municipal tax, however, is calculated on a ‘notional tax’, as if your French, Dutch or German salary were Belgian. You pay it even with no Belgian income at all. Luxembourg salary is exempt from it.

According to tax return guides, foreign salary is declared with your pay (code 1250, or 2250 for your spouse) and is also entered under foreign-source income in section IV, with the country. Tax-on-web does not pre-fill it. These codes come from a secondary source: check them in that year’s tax return guide. For the effect on your tax assessment notice (aanslagbiljet / avertissement-extrait de rôle), see tax refund or tax to pay.

Social security, health care, family allowances

In principle, you are insured in the country where you work. If you work at least 25% of your time in Belgium, Belgium becomes the competent country: your employer must then register with Belgian social security. Since 1 July 2023, a European framework agreement allows you to remain insured in the employer’s country with less than 50% teleworking in Belgium, at the joint request of the employer and the worker.

Working time in BelgiumSocial securityStep
Below 25%Employer’s countryNothing to do
From 25% to less than 50%, teleworkingEmployer’s country, on requestYour employer applies for the framework agreement and an A1 form
From 25% to less than 50%, other activity in BelgiumBelgiumYour employer registers with Belgian social security
50% or moreBelgiumYour employer registers with Belgian social security
Share of your working time in Belgium and the country of your social security. Sources: Regulations (EC) No 883/2004 and 987/2009, FPS Social Security.

Health care: ask your insurer in the country of employment for an S1 form and register it with a Belgian health insurance fund. You are treated in Belgium like anyone insured in Belgium, and you can also receive treatment in the country of employment.

Family allowances: the country where you work pays first. If the other parent works in Belgium, Belgium pays first. The country that does not pay first pays the difference if its allowances are higher.

Frequently asked questions

I telework two days a week for a Luxembourg employer: what happens?

Two days a week makes about 90 days a year, far more than the 34 days tolerated. Belgium then taxes all your days working from home, from the first one. For social security, with about 40% teleworking, you can remain insured in Luxembourg if your employer applies for the framework agreement.

Does the 34-day rule also apply to France or the Netherlands?

No. This tolerance only exists with Luxembourg. With France, the Netherlands and Germany, every working day in Belgium is taxable in Belgium.

Why pay municipal tax on a salary taxed abroad?

Because the treaties with France, the Netherlands and Germany allow it: the municipal tax is calculated on the tax you would pay if that salary were Belgian. The Constitutional Court has upheld this several times. Luxembourg salary is exempt from it.

Does my foreign salary push up my Belgian tax?

It is not taxed in Belgium, but it counts for the rate applied to your other Belgian income and your spouse’s, under joint taxation (exemption with progression). With no other Belgian income, there is no Belgian federal tax to pay, only the municipal tax, except for Luxembourg.

What next?

Sources

Parameters in force on 1 October 2026. Each parameter links to its source, the official one where it exists; a secondary source is flagged as such.