Employer social documents: overview and obligations

The social inspectorate is at your door. An unannounced check. The inspector asks for your work regulations, your employees' individual accounts, and the staff register. Are those documents ready? Do you know where they are? And are they complete?

For many employers, this is the stuff of nightmares. Not because they have anything to hide, but because the paperwork around social documents is genuinely complex. Which documents are mandatory? How long do you have to keep them? And what happens if something is missing?

This article gives you a complete overview of every social document you need to keep as an employer. No legal jargon, just practical guidance you can put to use straight away.

What are social documents and why do they matter?

Social documents are the official records every employer in Belgium must draw up and keep. They serve several purposes: they protect your employees' rights, they ensure social security contributions are calculated correctly, and they make inspections by the authorities possible.

The legal basis is Royal Decree no. 5 of 23 October 1978 on the keeping of social documents. According to FPS Employment (Federal Public Service Employment, Labour and Social Dialogue), employers, persons treated as employers, and anyone who employs apprentices must draw up and keep these documents.

These are documents you need from the moment you take on your first employee. No exceptions.

Mandatory documents when hiring

Hiring someone triggers a whole series of administrative obligations. Here are the documents you need.

The employment contract

The employment contract is the foundation of every working relationship. While a verbal contract is in principle legally valid for some types, a written agreement is always advisable. For certain contract types, putting it in writing is even mandatory:

• Fixed-term employment contracts
• Part-time employment contracts
• Contracts for clearly defined work
• Student contracts

The contract must be signed no later than the moment the employee starts work. Not the day after, not next week.

The Dimona declaration

You must register every employee with the NSSO (National Social Security Office) through the Dimona system before they actually start working. Dimona stands for immediate employment declaration (Déclaration Immédiate / Onmiddellijke Aangifte), and the declaration has to be made at the latest at the moment employment begins.

The declaration is submitted electronically through the social security portal. File it late? You risk a fine that can run into hundreds of euros per offence. We previously wrote a detailed guide to Dimona declarations for temporary workers that walks you through the process step by step.

The staff register

Every employer must keep a general staff register. It contains the basic details of all your employees:

• Registration sequence number
• Surname and first name
• Date and place of birth
• Gender
• Place of residence
• Nationality
• Start and end date of employment

Do you work with temp workers or trainees? Then you also need a special staff register to record these temporary workers.

After more than 15 years in Belgian payroll, we see that the staff register is often forgotten or left incomplete, especially during fast growth phases. Make sure you keep this document up to date.

Work regulations: mandatory from your first hire

This is where it gets legal. Work regulations are mandatory the moment you take on your first employee: the Act of 8 April 1965 establishing work regulations is crystal clear about it.

This applies to both the private and the public sector. No thresholds, no exemptions for small businesses.

What must it contain?

The law lists a whole range of mandatory details. The most important ones:

• The start and end of the normal working day
• The timing and length of rest breaks
• Days of regular interruption of work
• How work schedules are announced
• The method and date of wage payment
• Notice periods and grounds for dismissal for serious cause
• The rights and duties of supervisory staff
• Penalties and the amounts of the fines
• The employee's options to appeal
• A reference to the applicable collective labour agreements (CLAs)
• The addresses of the inspection services

New since 2026: the work regulations must also include a clear procedure for maintaining contact with employees on work incapacity. This covers the communication arrangements and the internal contact persons responsible for follow-up.

How to draft and amend it

You can't simply write work regulations yourself and impose them on your staff. There's a legal procedure that gives employees a say:

1. You draw up a draft
2. For 15 days, employees can submit comments
3. If there are comments, you work towards an agreement
4. If a dispute persists, you can call in the social inspectorate

Do you have a works council? Then the procedure runs through that body.

Filing with FPS Employment

Within eight days of it taking effect, you must file the work regulations (or any amendment) with FPS Employment. You can do this online at www.arbeidsreglement.belgie.be.

Every set of work regulations must also be posted in a visible and accessible spot in your company. New employees receive a copy when they start, on paper or digitally.

The payslip: a monthly obligation

Every employee is entitled to a payslip with each final payment of wages. In practice, that means monthly for most workers.

Mandatory details on the payslip

The payslip must contain at least the following:

Identification details:

• The employee's name, address and national register number
• The employer's name and address
• The pay period

Pay details:

• Total gross salary
• A breakdown of the gross salary: hours worked, overtime, pay for equivalent days
• Benefits in kind (with their value)
• NSSO contribution (social security)
• Professional withholding tax
• Other deductions
• Net salary

Some joint committees impose additional requirements. In JC 124, for example, the mobility allowance must be listed.

At Recruit, we generate payslips automatically and fully in line with the legal requirements, including all the sector-specific details that apply to your joint committee. So you don't have to keep track yourself of which extras are mandatory for your sector.

Attachments for special work arrangements

Do you work with overtime, flexible working arrangements or commission-based pay? Then you must add attachments to the payslip. These attachments must be given to the employee together with the payslip and kept for five years.

The individual account: annual overview

The individual account is the annual summary of all pay and working-time data for each employee. You must draw it up and close it every year.

What does it contain?

The individual account brings together all the data from the past year:

• Employee identification details
• All salary components
• Days worked and equivalent days
• NSSO contributions
• Professional withholding tax
• Holiday pay and end-of-year bonus

This document is crucial for calculating social rights such as pension, sickness benefit and unemployment. The data is also forwarded through the DmfA to all the social institutions involved.

Documents when employment ends

When an employee leaves your company, for whatever reason, you're required to hand over a series of documents.

The C4 form (unemployment certificate)

The C4 (form) is probably the best-known document when employment ends. You must hand it to every employee whose contract comes to an end. Always. Whether the employee resigns, is dismissed, or a fixed-term contract simply expires.

Even at the end of a student contract or on retirement, you must issue a C4.

The C4 must contain:

• The employee's name, address and national register number
• The employer's details
• The start and end date of employment
• The reason the contract ended
• Information on any severance pay

The deadline? You must hand over the C4 no later than the last working day. You can also do this electronically through the social risk declaration (e-ASR), scenario 1, at www.socialsecurity.be.

The holiday certificate

The holiday certificate states the holiday rights the employee has built up. It lets the employee work out their entitlement to annual leave with a new employer.

The tax form 281.10

The tax form 281.10 sets out all remuneration, commuting allowances, expense reimbursements and benefits in kind. You must draw up this form every year, but when someone leaves you must also inform them of the amounts up to that point.

The employment certificate

At the employee's request, you must issue an employment certificate. This is a simple document showing only the start and end date of the contract and a short description of the role performed.

Be careful: you may not include any other information in this certificate. No assessments, no references to incidents, nothing that could harm the employee in their search for new work.

Retention periods: how long to keep what?

This is where many employers come unstuck. The basic rule is simple, but there are nuances.

The five-year rule

Most social documents must be kept for five years:

• General staff register: 5 years from the last mandatory entry
• Special staff register: 5 years from the last mandatory entry
• Individual account (and attachments): 5 years from the annual closing
• Payslip attachments: 5 years

Where can you store them?

You have a few options for where to keep them:

• At the address where you're registered with the NSSO in Belgium
• At your place of residence or registered office in Belgium
• At your social secretariat (only for the individual account and attachments)

As for the format, you can keep them on paper, microfiche, film or digital media. Many employers now opt for digital storage. With a system like Recruit, all social documents are automatically archived digitally and kept for the legally required period. No boxes full of paper, no hunting around during an inspection.

Tax documents: a longer period

Watch out: for tax documents, a retention period of 10 years instead of 7 years has applied since assessment year 2023. Think of payroll records that are also relevant for tax purposes.

The DmfA quarterly declaration

The DmfA (multifunctional declaration) is the electronic quarterly declaration you must submit to the NSSO as an employer.

What does the DmfA contain?

The DmfA brings together the pay and working-time data of all employees who worked for you during a given quarter. Based on this, the system calculates how much social security contribution you owe.

A key advantage: the data is automatically forwarded to all the social institutions involved. That saves you filing separate declarations.

Filing deadline and penalties

You can submit the declaration from the first day of the month following the quarter. Deadline: the last day of that month.

In concrete terms:

• Quarter 1 (January to March): file in April
• Quarter 2 (April to June): file in July
• Quarter 3 (July to September): file in October
• Quarter 4 (October to December): file in January

Late or not submitted? The NSSO charges a flat-rate compensation of €495.79, increased by €247.89 per bracket of €24,789.35 in contributions above €49,578.70. That adds up fast.

For an incomplete or incorrect declaration: €50 for the correction, plus €4 per missing or amended employment line.

Most employers have their social secretariat or payroll partner handle the DmfA declaration.

Digital vs. paper: what's allowed, what's required?

Legislation is keeping pace with digitalisation. More and more documents can be drawn up and kept entirely digitally.

What can be digital?

• Payslips: can be created and delivered electronically
• Individual account: can be kept on digital media
• Staff registers: a digital form is allowed
• Work regulations: can be delivered to employees digitally
• C4 form: can be submitted electronically via e-ASR

Important conditions

Digital storage does come with conditions:

• The documents must remain legible and accessible for the entire retention period
• You must be able to prove the documents are authentic
• During an inspection, you must be able to produce the documents quickly

In our experience with thousands of temporary workers, digital documentation isn't just more convenient, it's also more reliable. No lost papers, no faded printouts, and instant access during an inspection.

Frequently asked questions

As an employer with just one employee, do I really need all these documents?

Yes. From the very first employee, all the obligations apply. The work regulations, the staff register, the payslips, the individual account: everything is mandatory. The only exception is that small businesses without a works council go through the work regulations procedure directly with their employees.

What if I've lost a document?

Try to reconstruct it. For many documents you can request copies from the NSSO or your social secretariat. During an inspection, proactively report what's missing and what you've done to solve the problem. Inspectors value honesty and active cooperation.

Can I outsource all my social documents?

Yes, largely. A social secretariat or payroll partner can draw up and keep most documents for you. But as the employer, you remain ultimately responsible. You must be able to show that the documents exist and are correct.

Do the same rules apply to flexi-jobbers and students?

The rules are largely the same, with a few particularities. For students, for instance, you have to draw up a specific student contract. And for flexi-jobbers and students too, the Dimona obligation applies and you must issue a C4 when their employment ends.

What are the penalties for breaches?

Penalties range from administrative fines to criminal prosecution for serious or repeated breaches. Fines can run from a few hundred to several thousand euros per offence. In cases of systematic infringements, the inspectorate can even shut your business down.

In short

Social documents aren't optional. As an employer in Belgium, you have to draw up, maintain and keep a whole series of documents. From work regulations to the C4, from the payslip to the individual account.

The key points at a glance:

• Work regulations are mandatory from your first employee
• A Dimona declaration for every employee, before employment starts
• A payslip with every wage payment
• Close the individual account every year
• When employment ends: the C4, the holiday certificate and the tax form
• Retention: 5 years for most social documents
• The DmfA quarterly declaration within the month after each quarter

The admin is extensive, but not insurmountable. With good organisation, or a partner who takes it off your hands, you avoid surprises during an inspection.

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How Recruit helps you

Would you rather focus on your core business than on payroll admin? That's exactly what Recruit is for.

With Recruit:

• Contracts in under 60 seconds: create trial and temp contracts without the hassle
• Automatic wage calculation: correct pay in line with current legislation and your joint committee
• Dimona and social documents: we handle every declaration, you focus on your business
• 24/7 personal support: always a dedicated contact who knows your company
• No fixed monthly costs: pay only for what you use

Try Recruit or get in touch with our HR experts for tailored advice.

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The information in this article is purely informative and does not replace professional legal or accounting advice. Labour legislation changes regularly. Always consult the current legislation or contact an HR expert for advice tailored to your situation. Please note: the rules can vary by joint committee and sector.