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How do I request a new identification number for my employee? (with SECUline)

When you hire an employee who doesn't yet have a Luxembourg social security number (matricule), Salary.lu can request one from the CCSS for you through SECUline. This article explains how to submit the request so it isn't rejected.

If your employee already has a Luxembourg social security number, you don't need this procedure. Enter the number directly in their profile, then tick the entry-declaration box at the end of the form when adding their contract on the "Contracts" tab.

Before you start

Confirm that SECUline is active for your company — you'll see a small SECUline tag on your company page, just below the company name. If the tag isn't there, this procedure won't be available.

Requesting a new identification number

Go to the employee's profile
Tick the box "Request a new identification number (if the employee does not already have one)", this opens the "Matricule request (CCSS)" panel
Indicate whether the employee is an EU, EEA or Swiss national
Indicate whether the employee resides in Luxembourg
Select the type of identity document. Salary.lu confirms whether it's accepted and tells you what to attach
Upload a colour scan of the document. You can upload an image or a PDF, Salary.lu converts it automatically and shows a preview (CARTID.jpg)
Review the preview and confirm each item in the checklist before sending

The request is sent to the CCSS the following morning.

Document quality is the most common reason for rejection. Before sending, make sure the document is compliant thanks to the checkboxes.

Important points

The CARTID file transfers the scanned identity documents to the CCSS, and the DEMMAT file contains the employee's contact information and the request for a social security number.
The CCSS processes the request and automatically assigns a Luxembourg social security number to the employee if they don't already have one.
Both the employer and the employee are notified once the number has been assigned.

If you run into any difficulties, reach out via our online chat or at info@salary.lu.

Updated on: 09/06/2026

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