DEMMAT - SECUline

What is DEMMAT? — DEMMAT is a SECUline procedure used by employers in Luxembourg to request a social security number for an employee who does not yet have a Luxembourg social security identification number. This electronic file contains the employee's contact details and personal information necessary for the Joint Social Security Centre (CCSS) to create or identify the individual's social security number in the Luxembourg system.

When should an employer use the DEMMAT procedure? — Employers must use DEMMAT when hiring an employee who is working in Luxembourg for the first time and does not have a Luxembourg social security number. This typically applies to new cross-border workers from EU, EEA, or Swiss countries, or when an employee's social security number is unknown to the employer. The DEMMAT request must be submitted before the employer can complete the employee's formal affiliation declaration through the DECAFF procedure.

What information must be included in a DEMMAT file? — The DEMMAT file requires comprehensive employee information including:

How does the DEMMAT process work for EU, EEA, and Swiss nationals? — For employees from EU, EEA, or Swiss countries, the employer submits the DEMMAT file along with a scanned identity document via the CARTID procedure through SECUline. The CCSS reviews the submission and creates the social security number based on the identity document provided. The CCSS then communicates the assigned social security number back to the employer through the MATASS file, allowing the employer to proceed with the DECAFF declaration of entry.

What is the procedure for non-EU, EEA, and Swiss nationals? — For employees from outside the EU, EEA, or Switzerland, the social security number creation process differs significantly. The General Department of Immigration creates the social security number at the start of the residence or work permit application procedure. Once the permit is granted and the social security number is assigned, the employer can directly complete the DECAFF file for employee affiliation without needing to use the DEMMAT procedure.

What happens if the CCSS cannot create the social security number? — If the CCSS encounters issues with the DEMMAT request, such as an illegible identity document or incorrect data in the submission, they will send a MATRET file to the employer indicating that the social security number cannot be created. The employer must then correct the DEMMAT file or submit a new CARTID file with improved documentation quality, and resubmit the request through SECUline.

How long does the DEMMAT process take? — Once the employer submits a complete and accurate DEMMAT request with proper identity documentation, the CCSS typically processes the request and assigns a social security number within approximately two weeks. Both the employer and employee receive automatic notification once the social security number has been assigned and the employee is registered in the Luxembourg social security system.

Synonyms: Social security number request, employee registration request, matricule request, identification number application