24 Day rule in the double tax treaty between Belgium and Luxembourg
The third amending protocol, signed on 5 December 2017, to the Belgium - Luxembourg Income and Capital Tax Treaty (1970), as amended by the protocols of 11 December 2002 and 16 July 2009, entered into force on 11 February 2022.
The protocol applies to salaries, wages and other remuneration relating to tax periods beginning on or after 1 January 2015.
Employees who are tax resident of Belgium and who work in Luxembourg for a Luxembourg employer, are, in principle, liable to tax in Luxembourg on their employment income but only in respect of the working days spent in Luxembourg. If they work from home or if they work in another country (e.g. on a business trip), their income for these working days outside Luxembourg are normally liable to tax in Belgium and not in Luxembourg.
The agreement signed between Belgium and Luxembourg on 5 December 2017 introduced an exception. Since 1 January 2015, Belgian residents who are working for a Luxembourg employer in Luxembourg, are allowed to work outside Luxembourg for a maximum of 24 days per calendar year, where they are deemed to have worked physically in Luxembourg (and vice versa).
This is a tolerance for working days outside Luxembourg (at home in Belgium or elsewhere) allowing Luxembourg to tax the employment income for these days (with a maximum of 24 working days).
A new tolerance of 34 days in 2022
Within the context of the COVID-19 pandemic, there have been tolerances since March 2020 allowing workers working from home and still being taxed in the work state. These have been extended until the end of March 2022.
On 31 August 2021, an agreement was signed to extend the “24-day rule” to a “34-day rule” from 2022. See also Luxembourg and Belgium allow more teleworking days.