Two social-security filings, each within 8 days, plus the contract, the tax card and the monthly payroll: the full checklist for a clean first hire in the Grand Duchy.

In short. Hiring your first employee in Luxembourg comes down to two social-security filings, each due within 8 days. First you register the company as an employer with the Joint Social Security Centre (CCSS), which assigns it a permanent employer registration number. Then you file the employee's entry declaration, which enrols them and opens their cover. On top of that sit the written contract, the tax withholding card and the monthly wage declaration.

A first hire is a threshold. You move from sole director to employer, with obligations that do not reward improvisation: an employee not declared on time means a fine and social cover left hanging on the day of an accident. The good news is that the Luxembourg circuit is short and clearly marked. Here, in order, is what it takes to hire cleanly in the Grand Duchy, with the deadlines that matter and the slips that cost.

What are the steps to hire an employee in Luxembourg?

Hiring an employee in Luxembourg requires two declarations to the Joint Social Security Centre, each within eight days: registering the company as an employer, then filing the employee's entry declaration. You also need a written employment contract, the employee's tax withholding card and, from then on, the monthly wage declaration.

Step 1: register your company as an employer

Until you have an employee, your company is not known to the Joint Social Security Centre as an employer. The first hire therefore triggers a registration. It is done through an operating declaration (déclaration d'exploitation), submitted via MyGuichet.lu or on the paper CCSS form, within 8 days of the first employee's start date.

The declaration carries the 13-digit national identification number, the company's name and address, its RCS registration number for a company, its incorporation date and a description of the activity. In return, the CCSS sends you a letter confirming enrolment and assigning an employer registration number (matricule-employeur). That number stays with the company for its whole life, barring a change of legal form: you never repeat this step for later hires.

Step 2: file the employee's entry declaration

This is the central formality, and the most closely watched. The entry declaration (déclaration d'entrée) enrols your employee in the social security system and opens their cover: health and maternity, accident, long-term care and pension insurance. It is filed through SECUline using the DECAFF procedure, via MyGuichet.lu, or on paper, within 8 days of the start date. Once the affiliation is recorded, both the employee and the employer receive an automatic confirmation.

The declaration asks, as a minimum, for the employee's national identification number or date of birth, their name and address, the job description and the number of weekly hours, the four-digit occupation code under the CITP-08 classification, the country where the work is carried out, and any status as a director together with a shareholding percentage. Nothing insurmountable, provided you have this information to hand on the start date.

The 8-day deadline and what it costs to miss

The legal deadline is eight days, but a 30-day tolerance applies before penalties start to run. Beyond that, a late declaration exposes you to a fine of 50 € per month of delay, capped at 2,500 €. The real risk, though, is not the fine: it is the period during which your employee works with no affiliation recorded. Should a workplace accident occur before the declaration, matters get complicated for everyone. The rule is easy to keep: you declare before or on the start date, never "when there's time".

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Step 3: the written employment contract

In Luxembourg, the employment contract is concluded in writing, at the latest when the employee starts. It sets out, among other things, the identity of the parties, the start date, the nature and place of the work, the weekly hours, the agreed pay and, where relevant, the trial period and the end date for a fixed-term contract. Luxembourg employment law falls under the Labour and Mines Inspectorate (ITM), not social security: these are two separate worlds, and a clean hire means dealing with both. We produce your payslips and your social filings; for drafting and legally securing the contract, a specialist employment-law adviser remains the right port of call.

Step 4: the tax withholding card

Luxembourg salaries are taxed at source: the employer withholds the tax on each payslip and remits it to the Direct Tax Administration. To apply the right amount, the employer needs the employee's tax withholding card (fiche de retenue d'impôt), now sent electronically, which states their tax class (1, 1a or 2) and any personal allowances. As long as that card is not available, the employer applies the maximum withholding, which penalises the employee on their first net pay. It is worth anticipating from the start, to avoid a distorted first payslip and a later adjustment. The full move from gross to net, class by class, is set out in our article on the Luxembourg payslip.

Step 5: the file's monthly life

Once the employee is affiliated, the obligation becomes recurring. Each month, the employer declares to the CCSS the gross wages paid and the exact number of paid hours for the previous month, through the DECSAL procedure in SECUline, within 10 days of the start of the month. The Joint Social Security Centre then calculates the contributions and issues a single invoice covering both the employer and the employee share: you pay the whole to the CCSS, the employee share having already been withheld on the payslip. Any undeclared pay exposes you to quarterly fines.

What will this hire cost you?

Beyond the formalities, the director's real question is the budget. On a gross salary, employer contributions add roughly 12.66 % to 14.78 % depending on your company's mutual insurance class, while the employee bears close to 12.45 % before tax. Someone paid the unskilled minimum wage of 2,771.33 € gross per month, the rate since 1 June 2026, therefore costs an employer a little over 3,120 € a month. We break that calculation down, mutual insurance class included, in our article on what an employee really costs in Luxembourg. If your recruit is a cross-border worker, the payroll mechanics are identical, but remote work outside Luxembourg can shift part of the taxation, a point covered in our guide to employing a cross-border worker.

The mistakes we see on a first hire

Three slips come up again and again. The first is the entry declaration forgotten or put off, because you think there is time: the eight-day clock starts on the start date, not at month-end. The second is the tax card not retrieved, which starts the employee on maximum withholding and produces an unfair first payslip. The third is confusing the social with the legal: you take care over the CCSS declaration but neglect the written contract, or the reverse. Caught in time, none of these is serious. Discovered under the pressure of an inspection or a first payslip, they turn into needless stress.

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Frequently asked questions

What is the deadline to declare a new employee in Luxembourg?

The entry declaration must reach the Joint Social Security Centre within 8 days of the start date. A 30-day tolerance applies before penalties; beyond that, a fine of 50 € per month of delay, capped at 2,500 €, may be applied.

How do you register as an employer in Luxembourg?

By submitting an operating declaration to the Joint Social Security Centre, via MyGuichet.lu or on paper, within 8 days of the first employee's start date. The CCSS then assigns an employer registration number, valid for the whole life of the company.

Do you need a written employment contract for a first hire?

Yes. The employment contract is concluded in writing, at the latest when the employee starts. It falls under Luxembourg employment law and the Labour and Mines Inspectorate (ITM), which are separate from the social-security formalities.

How does the employer obtain the tax withholding card?

The tax withholding card is issued by the Direct Tax Administration and sent to the employer electronically. It states the employee's tax class. Where no card is available, the employer applies the maximum withholding until it is regularised.

What filings follow the hire?

Each month, the employer declares the previous month's gross wages and hours to the CCSS, within 10 days of the start of the month. The CCSS then issues a single invoice combining the employer and employee contributions.

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Why Advena?

We keep the books and run the payroll of Luxembourg SMEs of 1 to 50 employees, on a fixed fee from 325 € per month, all in. For a first hire, that means in practice that we take on the employer registration, the entry declaration, the payslips and the monthly filings with the Joint Social Security Centre, with the payroll entries flowing straight into the Odoo where we keep your books. Your payroll appears in your real-time position, not in a separate file. Let us be straight: if you plan to run several hundred payslips across multiple collective agreements, a specialist payroll bureau will serve you better, and we will say so at the first meeting.

Bookkeeping, VAT, annual accounts and payroll in one fee, quoted upfront. Let's talk about your first hire.

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Information current as at September 2026. The deadlines and procedures for employer registration and the employee entry declaration come from the guidance of Guichet.lu and the Joint Social Security Centre; the monthly wage-declaration obligation is set out on the CCSS employer pages. This article is for information and does not constitute personalised legal, tax or social advice.