Navigating Belgium’s Strict Private Investigations Act: What Employers and HR Professionals Need to Know

Main Facts: The High Stakes of Internal Workplace Investigations in Belgium

For decades, corporate internal investigations—whether probing financial irregularities, harassment claims, or breaches of internal policy—were treated as routine administrative tasks handled internally by Human Resources or corporate security teams. However, a stringent legal reality has taken root in Belgium, fundamentally altering how companies must approach workplace inquiries.

Under Belgium’s Private Investigations Act (PIA), the legal scope governing who can investigate, how evidence is gathered, and how reports are handled is remarkably broad. Crucially, internal workplace investigations conducted by a company concerning its own employees fall directly under the regulatory umbrella of the PIA. While HR professionals acting on behalf of their direct employer for internal "incident investigations" enjoy a limited exemption from holding formal investigator licenses and identification cards, they are entirely subject to the rigorous procedural safeguards outlined in the statute.

The legislative framework demands strict adherence to principles of proportionality, transparency, and civil liberties. Employers can no longer act as autonomous investigators operating outside the law. From the initial drafting of an assignment document to the final destruction of the investigation file three years later, every step of a Belgian workplace investigation is heavily monitored by regulatory bodies, including the Data Protection Authority (DPA) and specialized labor inspectors. Failure to comply can result in catastrophic legal consequences, ranging from administrative fines and GDPR penalties to the complete inadmissibility of evidence in court.

Chronology and Procedural Lifecycle of a Compliant Investigation

Conducting a workplace investigation under the PIA requires careful adherence to a strict chronological framework. The process is divided into distinct phases—before the start, during the execution, and after completion.

1. Before the Start: Documentation and Legitimate Interest

Before a single question is asked or any data is reviewed, the employer must establish a clear, documented "legitimate interest" in the investigation’s outcome.

• The Assignment Document: This interest must be formally codified in a written investigation assignment document prior to the investigation’s commencement. For internal investigation services, this must be logged in an official assignment register.
• Internal Regulations: Under the PIA, initiating an investigation into an employee is strictly prohibited unless the possibility of such internal investigations is expressly, clearly, and transparently outlined in the company’s internal regulations.

2. During the Investigation: Means, Methods, and Interviews

Investigators—whether external professionals or internal HR personnel—do not possess special police powers. They are restricted to standard civil rights supplemented only by what the PIA explicitly allows, and they must never infringe upon the individual rights and freedoms of the subjects.

• Property Access: Investigators are barred from entering non-public spaces without the explicit written consent of the person who has actual enjoyment of that space or their designated appointee.
• The Interview Process: Questioning a subject requires strict adherence to procedural fairness. Consent from the person being questioned is mandatory. Investigators must refrain from any leading questions, suggestions, threats, or psychological pressure that might compromise the interviewee’s freedom to respond. Detailed information regarding the scope and nature of the interview must be provided beforehand.
• Recordings and Documentation: If an interview is recorded via audio or video, the subject must be explicitly informed, prior consent must be secured (preferably captured within the recording itself), and the interviewee is entitled to a free copy of the file. Every interview must yield a formal written report.
• Prohibition of Entrapment: Investigators are strictly prohibited from inducing a subject to commit an act they would not have initiated on their own. The use of unlawful or offense-derived evidence is entirely banned.

3. After Completion: Notification and Reporting

Once the investigation concludes, a rigorous post-investigation timeline begins:

• The Final Report: No later than one month following the final investigative act, a written report signed by all involved investigators must be transmitted to the principal. In urgent scenarios, an initial oral report is permitted, provided it is followed by a comprehensive written report within eight working days.
• The 30-Day Notification Window: Within 30 days of receiving the final report, the principal must state in writing to the investigator whether it intends to act on the information (either by taking immediate employment or legal action, or by archiving the report to serve as a baseline for potential future investigations involving new facts).
• Data Retention: Investigation files must be securely maintained for exactly three years from the date of transmission to the principal, after which they must be permanently destroyed.

Supporting Data and Legal Boundaries

The PIA and surrounding Belgian labor regulations establish unyielding boundaries regarding what information can be gathered, how it is handled, and how it can be utilized.

Prohibited Fields of Investigation

The PIA explicitly forbids investigators from gathering or disclosing sensitive categories of personal data to the employer. This prohibition extends to indirect inference: investigators cannot compile and present information from which a principal can easily deduce protected personal categories without engaging in further independent intelligence gathering.

Data Minimization and Privacy Standards

All findings must strictly satisfy legal criteria for accuracy, adequacy, and relevance. Information gathered must be strictly limited to what is necessary for the specific purpose outlined in the original assignment document. Disclosure to third parties is heavily restricted; it is permitted only insofar as it is strictly necessary for the defense of the employer’s legitimate interests as defined in the assignment document. Making investigation reports public is entirely illegal.

The Dual-Layer Enforcement and Sanctioning Regime

Supervision of compliance is multi-faceted. Oversight is shared among the Belgian Data Protection Authority (DPA), local police services, and specially designated royal decree inspectors.

• Administrative Penalties: A designated sanctioning officer holds the authority to issue formal warnings, propose out-of-court settlements, or levy steep administrative fines.
• GDPR Intersect: Crucially, any official report establishing an infringement of the GDPR is automatically forwarded to the DPA. This triggers the DPA’s full enforcement arsenal, meaning employers face a dual-layer risk exposure—violating both the PIA and European data privacy laws simultaneously.

Official Responses and Judicial Scrutiny

When workplace disputes escalate to the courtroom, judges are legally mandated to scrutinize how evidence was obtained. Courts must actively verify whether private investigations were conducted in strict compliance with the PIA before assessing their evidential value.

When Evidence is Rendered Inadmissible

If a court determines that investigative findings violate statutory protections, it holds the power to attach zero legal effect to the evidence. Specifically, evidence can be thrown out if:

1. The investigative methods violated fundamental rights or the specific restrictions of the PIA.
2. The rules governing interviews, consent, or privacy were breached.
3. The data was gathered via entrapment or unlawful procurement methods.

The "Tainted Fruit" Limitation

It is important to note that a single procedural misstep does not automatically invalidate an entire investigation. If an employer utilized multiple working methods to establish the same set of facts, an unlawful application of one method does not legally taint other findings that are robustly supported by correctly and lawfully applied investigative techniques. Nonetheless, relying on flawed procedures introduces profound litigation risks for employers attempting to defend disciplinary dismissals or corporate lawsuits before Belgian labor courts.

Implications for Businesses and HR Practitioners

The expansive reach of Belgium’s Private Investigations Act carries profound implications for corporate governance, human resources management, and risk mitigation strategies across the country.

1. Operational Realignment for HR Teams

HR professionals accustomed to conducting internal inquiries into employee misconduct—such as workplace harassment, theft, or policy violations—must fundamentally overhaul their processes. While they remain exempt from holding formal private investigator licenses when investigating their own company’s staff, they must meticulously follow every procedural safeguard. Every interview must be documented, consent must be secured, and privacy thresholds must be respected.

2. Mandatory Internal Regulations

Employers must review and update their company rulebooks immediately. Because an investigation into an employee is illegal unless expressly and transparently permitted within internal regulations, companies that lack these clauses are currently exposed to severe legal vulnerabilities.

3. Looming Deadlines and Legal Counsel

With regulatory bodies such as the DPA and labor inspectorates actively monitoring corporate compliance, businesses operating in Belgium must treat workplace investigations with the same legal rigor as formal criminal or civil proceedings.

Looking ahead, legal experts emphasize that companies must prioritize updating their internal governance frameworks. As businesses prepare for upcoming regulatory milestones—such as updating internal regulations—consulting with specialized labor and employment legal counsel, such as Marga Caproni and the Belgian Labour & Employment practice at Squire Patton Boggs, is essential to ensure full operational compliance and mitigate the severe risks of administrative sanctions and inadmissible evidence.