Posting workers to Belgium: Declaration of Works
What every posting employer and (Belgian) service user should know about the Declaration of Works notification.
Are you involved in a construction project? Then you might have to declare the works to the Belgian Social Security Office before starting the activities in Belgium.
The main contractor is responsible for the Declaration of Works. Subcontractors have an information obligation. Not complying triggers a financial penalty equal to 5% of the works’ value.
Declaration of Works at a glance
What is a Declaration of Works?
Declaration of Works is an online mandatory notification tracking the size and value of construction sites. It also creates visibility about contractor chains.
When does a Declaration of Works apply to a project?
Works qualifying as ‘works to immovable goods’ are required to have a Declaration of Works if certain conditions are met. ‘Works to immovable goods’ is a very broad term, and covers much more than a traditional construction project. We recommend checking in advance whether your project comes within that definition. This obligation also applies to non-Belgian companies.
| The Declaration of Works applies… …if the works have a value of at least EUR 30,000 (excl. vat); or …if the works have a value of at least EUR 5,000 (excl vat) and at least 1 subcontractor is involved; or …if more than 1 subcontractor is involved, regardless of the works’ value. |
Who is responsible for the Declaration of Works?
The main contractor is responsible for the Declaration of Works. Any subcontractor relying on a further subcontractor (or sub-subcontractor) has an information obligation towards their principal.
What happens if I did not comply with the Declaration of Works obligations?
A financial penalty equal to 5% of the works’ value (excl. vat) is due. This penalty can be imposed on the main contractor who has not declared the works or on a subcontractor who has not complied with the information obligations.
| The Declaration of Works is linked to Checkin@work. More information about this presence registration can be found here. |
Filing a Declaration of Works
Use the online portal
A Declaration of Works must be filed electronically at the Declaration of Works portal. After having submitted all the requested information, an identification number will immediately be displayed. You will also receive the “Declaration of Works”- document to be displayed on the works’ site.
Are you a main contractor declaring the works?
If yes, then you need a Belgian company number. If you do not have a Belgian company number, you can arrange for such a number when declaring the works.
Are you a subcontractor?
If yes, then no Belgian company number is needed. A reference to the intra-community VAT-number or foreign identification number is sufficient.
What is the difference between the secured and non-secured portal?
Both a secured and a non-secured version of the portal exist. The secured version provides many more features. Obtaining access to the secured portal, requires a specific account and the appointment of a Principal Access Manager. To become a Principal Access Manager you need a Belgian identity number. If you are not in possession of such a number, then you will first need to apply for it.
Good to know
This information only gives a general overview of the rules and does not include a comprehensive and exhaustive overview of any specific, complementary and/or derogating requirements and/or formalities. For this reason, this information sheet must not form the basis of any decision concerning a particular course of action and must not be considered as legal advice. Obtaining further tailor-made advice is recommended.
ALTIUS’ Employment team is available to assist foreign employers considering posting workers to Belgium. Furthermore, the Altius’ employment team can provide further guidance regarding any additional employment and immigration-related formalities, registrations and obligations triggered by a posting set-up.
If you have any specific questions or would like more detailed information about this topic, then please contact Emma Van Caenegem, Sven Demeulemeester or Philippe De Wulf. More information is also available in our brochure.
Interested in our other articles about posting workers to Belgium? Click the link(s) below!
Posting workers to Belgium: Joint Committees
Posting workers to Belgium: Checkinatwork
Posting workers to Belgium: the Limosa notification
Written by
Recommended articles
Game-changing rules for managing sick leave: What every employer must know now
The landscape of employee incapacity has fundamentally shifted. Are you prepared? On 1 January 2026, new legal rules entered into force aimed at accelerating the reintegration of incapacitated employees. They include important changes to the reintegration track and the force majeure track, as well as the obligation for employers to include a procedure for maintaining […]
Read on
Be ready for the long-awaited Flemish duty of care obligation in the construction sector: update your agreements and compliance procedures now
From 1 January 2026, a duty of care obligation applies to clients [1] and (sub)contractors active in the construction sector [2]. Some years ago, the Flemish government launched the idea of optimising contractor chain responsibility schemes in case of illegal employment, but actual implementation has taken some time. In the meantime, the obligations have been […]
Read on
The 10 EUR meal voucher is officially here
In its Coalition Agreement, the government had already announced that during this legislative term, the maximum amount of meal vouchers would be increased twice by 2 EUR. A first increase – from 8 EUR to a maximum of 10 EUR – was published in the Belgian Official Gazette on 17 November 2025. As of 1 […]
Read on