Belgium's Private Investigation Act poses new risks for companies and in-house counsels

The Private Investigation Act (PIA), which came into force in December 2024, has significantly changed how internal investigations are conducted in Belgium, with courts already enforcing its provisions and demonstrating its reach to employers. The obligations are strict, the documentation requirements are extensive, and the sanctions have an immediate impact on evidence in dismissals or other proceedings. 

In December 2025, the Antwerp Labour Court declared an entire workplace investigation report null and void because the employer had exceeded the observation time limits under the PIA. The investigation report was ruled inadmissible.  

Building sound investigation processes and documentation, establishing a private investigation policy and training staff are among the practical steps organisations and in-house counsels can focus on in response to the legislation and as operational priorities. 

Broad reach

The PIA has a broad reach into organisations. The legislation when it took effect on 16 December 2024 replaced the 1991 legislation on licensed private detectives. Unlike the old regime, it covers both external and internal investigations, including those run by HR departments possibly assisted by legal, finance or IT teams. The PIA is sector-agnostic and, as a matter of public order, no one can contract out of it.

Private investigation activity is defined as activities carried out by a natural person, on the commission of a principal, which consist of collecting information about persons or concerning specific circumstances or facts committed by them, with the aim of protecting the principal's interests in an actual or potential conflict, or of tracing missing persons or lost or stolen goods. The PIA can apply to your internal teams upon conducting employee investigations but also to businesses conducting private investigation activities as a service to their clients.

In-scope internal teams

HR, legal, audit and compliance can be within its scope. For many companies, the key distinction is between two types of internal actors. An internal private investigation service carries out investigation activities on a structural basis, meaning the investigation activities form part of at least one employee's job description. Such a service requires a licence from the minister of home affairs prior to conducting investigations. Internal functions that may qualify include the HR, internal audit, legal or compliance teams. 

HR department staff do not, however, require a licence or identification card when conducting incident investigations concerning their own employees for the company's own needs. That exemption is narrower than it appears. It does not cover investigations into third parties or structural investigative work. All other provision of the PIA apply to HR department staff.

Forensic, digital work and private investigation companies

Companies undertaking forensic investigations, e-discovery and data analysis may also fall within the legislation's scope, to a certain extent, if their activities meet all conditions of private investigation activities under the PIA. Those that are in scope include businesses conducting forensic investigations, such as analysing financial information and electronic communications, and interviewing witnesses to determine sequences of events. 

Those leading data analytics in high-profile litigation and regulatory investigations can also be in scope, including as expert witness, using data analysis tools to detect sanctions breaches and performing graph analysis of transactional data to detect financial crime; as can those using people and technology to help their clients identify, collect, analyse and review electronic documents and data to locate key evidence, including by helping prepare and implement e-discovery systems and forensic analysis of computers and mobile devices.

Moreover, a private investigation company cannot carry out activities other than the private investigation activities for which it holds a licence, except for security consultancy services. When an organisation engages an external investigator, they will need to check that they hold the license and that their assignment stays within that perimeter.  Commissioning an investigator who does not hold the required license or one asked to perform activities that fall outside their licensed activities exposes both the investigator and company to sanctions, and risks undermining the findings.

Setting up internal rules is mandatory

Before commissioning an employee investigation, a company must set up internal rules on employee investigations by 16 December this year. That document must set out the authorisation to conduct private investigations in the workplace and the practical rules governing them: what can be investigated, by whom, using which methods, where and under what circumstances. 

No specific form is prescribed: a company policy is a workable approach. What matters is that the document exists before the investigation begins. Failure to comply will lead to the investigation being deemed null and void by a court. 

Hard limits 

The PIA draws a firm line around certain categories of information: health data, trade union membership, among others. Crossing that line renders the entire investigation null. The risk in practice is rarely deliberate. It arises when an investigation into suspected misconduct incidentally touches on one of these categories. 

Belgian courts do not assess intent. They assess the outcome. If prohibited information was gathered or used, the findings go. Designing the scope of an investigation carefully, before it starts, is the most effective way to stay on the right side of this rule.

Required documents 

Each investigation requires a written assignment document; an assignment register will suffice where the investigator is an employee of the principal. Interviews require the subject's informed and free consent, preceded by a statement covering the purpose and their rights, including the right to refuse, to review the report and to assistance. 

A written file must be kept for three years. Once the employer receives the final report, a 30-day window opens to decide whether to act or not. Before doing so, the employer must notify all identifiable data subjects and allow them to exercise their rights under General Data Protection Regulation. 

Further considerations 

While professional activities carried out by lawyers fall outside the scope of the PIA up to a certain extent, in-house legal counsels do not benefit from this exemption. They require a licence and identification card when carrying out structural employee investigation activities internally. Only in limited circumstances might their occasional support to the HR team remove the identification card requirement; specifically, if they are not part of the investigation team and have no access to personal data or to the investigation report or its content. 

The territorial scope of the PIA is unclear. It contains no clarification on territorial scope, which leaves open the question of whether an internal investigation within an international group of companies that is conducted entirely digitally by a general counsel based outside the European Economic Area – for example, in the US or the UK –  into a Belgian subject falls within its scope. The safest approach is to apply the PIA whenever the investigation concerns a Belgian employee, given that  the results may need to serve as evidence before a Belgian court.

Osborne Clarke comment

Businesses operating in Belgium, including international groups conducting internal investigations into Belgian employees, should consider a range of measures to help to ensure that they fulfil their obligations and comply with the Private Investigation Act.

• Audit current investigation practices, job descriptions and existing policies, such as ethics codes, disciplinary and grievance policies and compliance standards.
• Identify what roles and teams conduct employee investigations internally.
• Assess whether they fall under the scope of the PIA and require a license and identification card prior to conducting employee investigations or whether they are exempt,
• Set up a private investigation policy by the 16 December deadline.
• Draft any template documents required.
• Train company staff on procedural requirements.