I want legal advice
Why is joint and several liability important?
We have found that the liability regime in such sectors as construction is insufficiently known – and unjustly so. Nevertheless, every (professional) client and contractor, whether main or subcontractor, bears responsibility in this respect. In other words, if individuals are illegally employed on your project or site by a contractor or subcontractor, this may also have consequences for you.
A private individual who commissions construction works can only be held liable if it is demonstrated that he was aware of the illegal employment.
On 1 January 2026, an additional duty of care was introduced, requiring business owners to compile a comprehensive file.
What does this joint and several liability entail?
It concerns liability in the event of the employment of illegally residing third-country nationals as employees or self-employed persons. ‘Third-country nationals’ refers to individuals holding a nationality from outside the EEA and Switzerland.
Important to note: this legislation applies to sites located in the Flemish Region, regardless of which undertaking (domestic or foreign) carries out the works.
To which sectors does this joint and several liability apply?
This liability regime applies in high-risk sectors, such as:
However, the regime extends beyond these sectors and also applies in other areas of activity.
Are you active in one of these sectors? If so, it is advisable to review your working methods and checks in advance to avoid any unpleasant surprises.
So how should you proceed as a client or contractor?
1) Obtain a written declaration from your (sub)contractor
Request a written declaration from your (sub)contractor confirming that they do not employ, and will not employ, illegally residing third-country nationals as employees or self-employed persons.
2) Comply with the duty of care: compile a file
A file must be compiled containing the personal data of everyone working on the project:
(sub)contractors (check the application of declaration 30bis)
obtain passports of foreign workers
obtain proof of lawful residence
obtain proof of registration in the LIMOSA database or Dimona notification
A1 certificate
3) Notification obligation: declare works under ‘30bis’ to the National Social Security Office
Works falling under ‘30bis’ must be declared to the National Social Security Office (construction and cleaning sectors):
Declaration of works: General information – About 30bis – Social Security
4) Withholding obligation: checks when paying invoices
When paying invoices, you must verify:
Reference: Article 30bis – Withholding obligation – Social Security
5) Record-keeping obligation: retain documentation for at least 5 years
The documentation must be retained for a minimum of 5 years.
When the requested information is not provided or if there is reason to believe it is false, this must be reported via the social security website, where you must first log in as a business.
Would you like to translate these obligations into a practical checklist for your business, including which documents you should routinely request? We will be happy to assist you.
What sanctions do you risk in the event of non-compliance?
If you fail to comply with the above obligations and your (sub)contractor is found to employ illegal workers, then as a professional client or contractor you risk the following sanctions:
a prison sentence of 6 months to 3 years and/or a criminal fine of €4,800 to €48,000
an administrative fine of EUR 2,400 to EUR 24,000
The fine is multiplied by the number of employees to whom the infringement relates. However, the multiplied fine may not exceed 100 times the maximum fine.
When do these obligations not apply?
A private client who is not aware of who is employed by their contractor.
Works amount to less than EUR 30,000, excluding VAT, and are carried out by a single contractor without a subcontractor.
Works amount to less than EUR 5,000, excluding VAT and involve just one contractor and one subcontractor.
The parcel delivery driver uses a vehicle subject to tachograph requirements
Need assistance?
Joint and several liability requires proper preparation: obtaining the correct declarations, carrying out the necessary checks and compiling your file in a timely manner. In particular, with the additional duty of care that came into effect on 1 January 2026, it is advisable to carefully check your approach in advance.
Do you have a site or collaboration planned? Please feel free to contact us. Together, we will assess which steps you should take and which documents you should retain.
Source: Joint and several liability | Vlaanderen.be
