Advocaten / Avocats / Lawyers

Tuesday, 07 September 2021

International Tax update: The Belgium - Luxembourg 24 day-rule becomes the 34 day-rule

The salary of a Belgian tax resident relating to days performed in Luxembourg is generally taxable in Luxembourg according to the Belgium-Luxembourg double tax treaty. The days worked outside of Luxembourg are then taxable in Belgium (state of residence).

Belgian tax resident working in Luxembourg

Since 2015, however, an executive agreement between both countries provided a tolerance according to which the salary of such Belgian resident is fully exempt in Belgium and exclusively taxable in Luxembourg if he has not worked for more than 24 days outside of Luxembourg. E.g., if he has worked 20 days from home, the salary related to these 20 days is not taxable in Belgium.  This tolerance is not exactly legally sound, but would be retroactively rectified by a protocol to the Belgium-Luxembourg double tax treaty. On 17 August 2021, the endorsement procedure for this protocol was initiated in the Belgian federal parliament.

During the Covid-19 pandemic many workers were forced to work much more or even exclusively from home. To mitigate the consequences of this, executive agreements have been concluded between the Luxembourg and Belgian tax authorities. Belgium has also concluded similar agreements with its other neighbouring countries, for that matter see newsflash published 25 June 2021. Now, and after years of rumors that the 24 day-rule would be extended to 48 days (see also newsflash published 20 April 2021) the Belgian and Luxembourg authorities have publicly announced that an agreement in this regard was reached.

As part of a larger agreement between both countries, the compromise now reached is 34 days. Starting in 2022, a frontier worker in the Belgium – Luxembourg context would be able to work for 34 days outside the state where he usually performs his work, while remaining liable for tax in that state.

As this is laid down in an executive agreement, it appears that endorsement by the legislature will be required. But on the other hand, the previous 24-day rule was also only laid down in an executive agreement and has been consistently applied since 2015.

A Belgium – Luxembourg cross-border worker will therefore be able to work from home 10 days more than at present before the salary relating to these activities becomes liable to tax in his residence state. This will undoubtedly impact and be welcomed by several cross-border workers. Employers should nonetheless stay aware of another important risk attached to having (key) employees working from home, being the risk that an employee’s home office would result in a permanent establishment. For this we refer to our newsflash published 25 May 2021.

Rik Smet - Associate (

Laurine Vanherck - Associate (

Tiberghien’s international tax team will continue to monitor these and other tax developments relevant for Belgium / Luxembourg based multinational enterprises. Our editorial board consists of:

In case you have further questions on this publication or want to discuss a tax query, please do not hesitate to contact the author(s) or one of the members of the editorial board.

This newsflash is for information purposes only and cannot be relied upon as legal advice.

Tiberghien Brussels

Tour & Taxis

Havenlaan|Avenue du Port 86C B.419
BE-1000 Brussels
T +32 2 773 40 00
F +32 2 773 40 55

Tiberghien Antwerp

Grotesteenweg 214 B.4
BE-2600 Antwerp
T +32 3 443 20 00
F +32 3 443 20 20

Tiberghien Ghent

Esplanade Oscar Van de Voorde 1
BE-9000 Gent
T +32 9 265 95 51

Tiberghien Hasselt

Koningin Astridlaan 35
BE-3500 Hasselt
T +32 11 57 00 13

Tiberghien Luxembourg

23, Boulevard Joseph II
LU-1840 Luxembourg
T +352 27 47 51 11
F +352 27 47 51 10