What does the warning message about the assimilation of resident taxpayers mean and what should I do?
The assimilation alert message appears on your account when the system detects that you do not automatically meet the criteria to be considered a Luxembourg tax resident. This has a direct impact on your taxation, as assimilation determines your entitlement to certain tax deductions.
To be treated as a Luxembourg tax resident, you must meet at least one of the following three conditions:
At least 90% of your household income is generated in Luxembourg.
The calculation of this percentage includes a special rule: the first 50 days worked abroad in the calendar year (e.g. teleworking) are considered as days worked in Luxembourg. This means that these days worked outside Luxembourg are ‘assimilated’ to Luxembourg income to make it easier to obtain resident status.
The household receives less than 13,000 euros net in income from abroad (outside Luxembourg).
This condition makes it possible to assimilate taxpayers who derive the majority of their income from Luxembourg, even if they have a limited source of income abroad.
For Belgian residents only: more than 50% of professional income is earned in Luxembourg.
This specific rule applies only to Belgian cross-border commuters, taking into account geographical proximity and bilateral tax treaties between Belgium and Luxembourg.
In the case of a married or civil union couple, it is sufficient for one of the two partners to meet at least one of these conditions for the household to benefit from assimilation.
If you think you meet the criteria but the alert message is still displayed, don't hesitate to contact our customer support team, either by email (help@taxx.lu) or via online chat, for help.
On the other hand, if none of the conditions are met, you cannot be treated as a Luxembourg tax resident. In this case, you will be taxed as a class 1 (non-resident), which means that you will not be able to benefit from the tax deductions granted to residents.
To be treated as a Luxembourg tax resident, you must meet at least one of the following three conditions:
At least 90% of your household income is generated in Luxembourg.
The calculation of this percentage includes a special rule: the first 50 days worked abroad in the calendar year (e.g. teleworking) are considered as days worked in Luxembourg. This means that these days worked outside Luxembourg are ‘assimilated’ to Luxembourg income to make it easier to obtain resident status.
The household receives less than 13,000 euros net in income from abroad (outside Luxembourg).
This condition makes it possible to assimilate taxpayers who derive the majority of their income from Luxembourg, even if they have a limited source of income abroad.
For Belgian residents only: more than 50% of professional income is earned in Luxembourg.
This specific rule applies only to Belgian cross-border commuters, taking into account geographical proximity and bilateral tax treaties between Belgium and Luxembourg.
In the case of a married or civil union couple, it is sufficient for one of the two partners to meet at least one of these conditions for the household to benefit from assimilation.
If you think you meet the criteria but the alert message is still displayed, don't hesitate to contact our customer support team, either by email (help@taxx.lu) or via online chat, for help.
On the other hand, if none of the conditions are met, you cannot be treated as a Luxembourg tax resident. In this case, you will be taxed as a class 1 (non-resident), which means that you will not be able to benefit from the tax deductions granted to residents.
Updated on: 05/06/2025
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