What are the employee’s obligations?

Any employee who is ill has 3 obligations in case of incapacity for work:

• He or she must first inform his or her employer on the first day of his or her absence. This can be done orally or in writing (email, fax, or SMS), personally or through an intermediary. This will provide the employee temporary protection against dismissal.
  
  
• Then, no later than the third day of his or her absence, the employee must submit to the employer a medical certificate (part no. 2) attesting to his or her incapacity to work and its expected duration. Compliance with this obligation then provides confirmed protection against dismissal.
  
  
• Finally, the employee must send the same medical certificate (part no. 1) to the Caisse Nationale de Santé (CNS) [National Health Fund] no later than before the expiry of the third working day of incapacity to work (with the postmark serving as proof). If the last day of this period is a Saturday, Sunday, or public holiday, the deadline is extended to the next working day.
  
  

Cross-border workers

• Belgian cross-border workers: As most certificates have only one part, it is advisable to request a duplicate from the doctor to give to the employer.
  
  
• French cross-border workers: The French work stoppage certificate includes a Part no. 1 (to be sent to the CNS) and a part no. 3 intended for the employer.
  
  
• German cross-border workers: The German form includes a Part no. 1 (to be sent to the CNS) and a Part no. 3 intended for the employer.
  
  

Where to send the certificates

• By post, at the following address: Caisse nationale de santé – Indemnités pécuniaires [National Health Fund – Cash Benefits] L-2980 Luxembourg
  
  
• Electronically via the following link: Declaration of incapacity for work – CNS – Luxembourg
  
  
• ATTENTION: For information, the address  cit.cns@secu.lu which could be used until recently, no longer exists as of 1 December 2024.

Specific situations:

• Employee’s incapacity for work for 1 or 2 days: The production of a medical certificate is not required by the CNS in such a case, but the company can require its employees to submit a certificate as of the first day of incapacity.
  
  
• Leave for family reasons: This leave can be taken by one of the parents if a child falls ill. A medical certificate is required for such leave from the first day of absence specifying the illness, accident, or other compelling health reasons for the child, the mandatory presence of the beneficiary with the sick child, and the duration of the presence with the child. The other declarative obligations are identical to those described above.
  
  

Employer reimbursement

The sick leave/family leave allowance is advanced by the employer to the employee provided that the latter is not covered by the CNS. The employer will be reimbursed by the Employers’ Mutual Insurance Fund via the social security bill (80% for work incapacities / 100% for family leave). This reimbursement will however occur only once the employer declares the incapacity to the Centre Commun de la Sécurité Sociale  (CCSS) [Joint Social Security Centre] and the employee sends their certificate to the CNS.