16 December 2026 may still seem some time away, but employers should now start preparing for an important deadline under the Belgian Act of 18 May 2024 regulating private investigations. The two-year transitional period provided for by the Act expires on that date. Employers who have not yet reviewed their internal framework for workplace investigations therefore have less than three months to do so.

The scope of the new Act remains a particularly important – and sometimes difficult- issue.

Broadly speaking, a “private investigation” involves gathering and processing information about persons or facts, at the request of a principal, in order to protect that principal’s interests in the context of an actual or potential conflict. The application of this definition to occasional, ad hoc internal investigations carried out by an employer remains open to discussion, particularly where the employer does not have a so-called “internal investigation service”. The position is much clearer where investigations are structurally conducted by such an internal investigation service or entrusted to external private investigators. This does not mean, however, that a one-off investigation necessarily falls outside the scope of the Act.

So what exactly needs to be done by 16 December 2026? Article 65 requires employers wishing to conduct private investigations involving their employees to have rules in place expressly and transparently providing for the possibility of such investigations and setting out the applicable conditions.

This is more than a formal compliance exercise: Article 101 expressly lists Article 65 among the provisions prescribed under penalty of nullity. Not having the required framework in place may therefore create significant difficulties when evidence gathered through an investigation is subsequently relied upon before a court.

The Act does not require the formal agreement of the social partners for the adoption of these rules. Nevertheless, involving or consulting employee representatives is advisable, both from a transparency perspective and to anticipate questions about how investigations may be conducted in practice. We would also recommend adopting the rules as a stand-alone policy rather than as an annex to the work regulations. This is a new and evolving area of law, and the policy will very likely need to be refined over time in light of legislative developments, legal literature and, importantly, the first court decisions interpreting the Act. Keeping it separate will make future adjustments considerably easier.

With less than three months to go, employers who have not yet addressed the issue should therefore put it on their agenda.

Younity is available to assist with drafting or reviewing the required internal rules, as well as with specific questions concerning the application of the Act to internal investigations.

For a more detailed overview of the new legal framework and its practical implications, see also Nicolas Roland’s practical guide on the Act of 18 May 2024 published in DPO News 2025/31, available through Anthémis and www.lexnow.io