In a decision dated 1 December 2025, the labour Court of Diekirch addressed a sensitive issue: how should the protection against dismissal during sick leave be reconciled with the situation of an employee who is a third-country national without a valid work authorization?
Under Article L.121-6 (3) of the Labour Code, an employee is protected against dismissal for a maximum of 26 weeks from the beginning of their incapacity for work, provided that the incapacity has been properly notified to the employer. At the same time, Article L.574-1 of the same Code strictly prohibits the employment of third-country nationals who are in an irregular situation.
In this case, the employee had been on sick leave for more than 33 weeks at the time of dismissal, thus exceeding the 26-week protection period. Therefore, under Article L.121-6 (3), the protection against dismissal would in principle no longer have applied.
Key point of the decision: irrespective of whether the 26-week threshold had been reached, the Labour Court noted that the employee did not hold a valid work authorization in Luxembourg. According to the Court, the legal provisions concerning illegal employment are matters of public order and do not provide for any exception for employees who are on sick leave, have complied with the requirements of Article L.121-6 of the Labour Code, and are nevertheless in an irregular administrative situation.
Consequently, when an employee is irregularly employed due to the absence of a valid work authorization, the protection against dismissal in case of illness does not apply. The employer must give priority to the mandatory provisions prohibiting illegal employment and must immediately terminate the unlawful employment situation.
This decision serves as an important reminder: regularly verifying and properly documenting the administrative status of third-country national employees is essential to mitigate legal risks.