Navigating Belgium’s Strict Workplace Investigation Rules: A Comprehensive Guide for Employers (Part Two)

Main Facts

Conducting an internal workplace investigation in Belgium is no longer a casual administrative task. As companies increasingly police themselves to address misconduct, harassment, or policy breaches, the legal framework governing these inquiries has drastically tightened. Building upon the foundational premise that internal corporate inquiries fall squarely within the scope of Belgium’s stringent Private Investigations Act (PIA)—as detailed in part one of this ongoing expert series—employers must navigate a complex labyrinth of statutory obligations, procedural safeguards, and strict limitations.

The PIA dictates every phase of a workplace investigation, from the initial paperwork to the final archiving or destruction of files. Far from enjoying blanket immunity or broad investigative liberties, employers and internal investigators—including Human Resources (HR) professionals investigating their own staff—are bound by rigid rules regarding transparency, privacy, proportionality, and consent.

Failure to comply carries severe consequences. Courts can completely discard evidence gathered unlawfully, and organizations face a dual-pronged enforcement threat from labor inspectors, police services, and the Belgian Data Protection Authority (DPA). With administrative fines, warnings, and potential GDPR penalties looming, understanding the procedural architecture of the PIA is no longer optional for business leaders operating in Belgium—it is an absolute operational necessity.

Chronology of an Investigation: From Initiation to Archiving

To ensure total compliance with the Private Investigations Act, employers must follow a strictly regulated chronological pathway when executing a workplace investigation. Every stage—before, during, and after the inquiry—carries mandatory legal milestones.

1. Before the Start: Legitimate Interest and Documentation

An investigation cannot begin on a whim. Before a single question is asked or piece of evidence is gathered, the employer must establish a clear, documented "legitimate interest" in the results.

• The Assignment Document: This legitimate interest must be explicitly captured in a written investigation assignment document prior to the investigation’s launch. For internal investigation services, this requirement is fulfilled via an official assignment register.
• Internal Regulations Prerequisite: Crucially, conducting an investigation into an employee is legally permissible only if the possibility of doing so is expressly and transparently outlined in the company’s internal regulations.

2. Execution, Means, and Methods

Once the investigation is greenlit, the investigator operates under tight legal tethers. The PIA explicitly states that investigators possess no special rights or powers. They may only perform acts available to any ordinary citizen, supplemented solely by what the PIA explicitly permits. Furthermore, methods must never impede the fundamental rights and freedoms of the subjects.

• Proportionality: Evidence gathering must be adequate, relevant, and strictly non-excessive relative to the private sphere of the individuals involved.
• Property Access: Investigators are barred from entering non-public spaces without the explicit written consent of the person who has actual enjoyment of that property, or their legally appointed representative.
• The Interview Process: Interviews are heavily regulated. Participation is voluntary, meaning the subject must consent to be questioned. Investigators are legally forbidden from utilizing questions, suggestions, threats, or any tactics that compromise the interviewee’s freedom to answer. Detailed information must be provided to the subject before the interview begins.
• Recording and Reports: If an interview is recorded via audio or video, prior consent is mandatory, the interviewee must be informed, and they are legally entitled to a free copy of the recording (ideally capturing the consent on the recording itself). Every interview must culminate in a written report.

3. Notification After Completion

Upon the conclusion of the investigation and the submission of the final report, the employer (principal) faces a strict 30-day window. Within this timeframe, the employer must state in writing to the investigator whether it intends to act on the information, choosing between two distinct legal scenarios:

• Scenario One: Immediate action based on the findings (e.g., disciplinary measures, dismissal, or legal escalation).
• Scenario Two: No immediate action, retaining the report strictly as a baseline or starting point for a potential future investigation should new facts emerge. (Employers opting to hold onto reports for future use are strongly advised to select this second scenario).

4. Reporting Deadlines and File Management

• Timeline: No later than one month after the final investigative act, the assignment holder must deliver a written investigation report signed by themselves and all participating private investigators. In urgent scenarios, an initial oral report is permitted, provided it is followed by a written report within eight working days.
• Data Quality: Findings must be lawful, accurate, adequate, and relevant.
• Confidentiality: Principals are prohibited from making the report public. Disclosure to third parties is permitted only to the strict extent necessary for the defense of the employer’s legitimate interests as outlined in the initial assignment document.
• Destruction Mandate: The investigation file cannot be kept indefinitely. It must be securely stored for exactly three years from the date of transmission to the principal, after which it must be destroyed.

Supporting Data and Exemptions: The HR Exception

While the rules are expansive, the legal framework provides a specific carve-out for internal corporate actors, though this exception comes with important caveats.

The HR Professional Exception

As highlighted in part one of this series, Human Resources professionals who carry out investigative activities on behalf of their own employer concerning an "incident investigation" involving their own colleagues are exempt from holding an official private investigator identification card and its associated licensing prerequisites.

However, employers must not mistake this licensing exemption for a free pass. All other substantive obligations under the PIA—including proportionality, interview consent rules, reporting deadlines, and data privacy limits—apply in full force to HR-led internal investigations.

Supervisory Framework and Dual Sanction Exposure

Compliance is heavily monitored by a coalition of authorities, including:

• The Belgian Data Protection Authority (DPA)
• Police services
• Specialized inspectors designated by Royal Decree

Sanctioning officers possess the authority to issue formal warnings, propose out-of-court settlements, or levy heavy administrative fines. Furthermore, because workplace investigations invariably touch upon personal data, any official report establishing a breach of the General Data Protection Regulation (GDPR) is automatically forwarded directly to the DPA. This exposes non-compliant companies to a dual-layer enforcement risk, combining employment law violations with severe data privacy penalties.

Official Responses and Judicial Scrutiny: What Happens When Things Go Wrong?

When an employer takes disciplinary or legal action based on a workplace investigation, the burden of compliance shifts to the courtroom. Judges in Belgium are mandated to verify whether the findings of a private investigation were obtained in strict accordance with the PIA and to independently assess their evidential value.

When Evidence is Tossed Out

A court may choose to attach zero legal effect to investigative findings under specific conditions:

1. If the findings violate fundamental rights or specific prohibitions outlined in the PIA.
2. If the investigation breached core procedural safeguards, such as conducting an interview without proper consent or failing to establish a legitimate interest via prior documentation.

The "Tainted Fruit" Nuance

Importantly, not all findings in a flawed investigation are automatically invalidated. Belgian legal principles recognize that if multiple working methods were deployed to establish the same factual matrix, a single unlawful method does not automatically taint findings that are simultaneously substantiated by lawfully applied methods.

Nonetheless, relying on sloppy investigative techniques is a gamble no prudent employer should take. A single procedural misstep can completely unravel a carefully planned termination or disciplinary action, leaving the company exposed to wrongful dismissal claims and regulatory fines.

Implications for Businesses and Future Outlook

The stringent reality of Belgium’s Private Investigations Act forces organizations to fundamentally rethink how they handle internal workplace issues. Companies can no longer treat internal inquiries as informal, backstage conversations. Every step—from drafting internal policies to conducting interviews and archiving files—must be treated with courtroom-grade precision.

Key Takeaways for Employers:

• Audit Internal Regulations: Ensure that employee handbooks and internal policies explicitly permit workplace investigations before any incident occurs.
• Formalize Assignments: Never launch an inquiry without a signed, written assignment document clearly stating the legitimate business interest.
• Train HR and Investigators: Ensure that internal personnel, including HR teams, understand the strict prohibitions against coercion, unauthorized surveillance, and privacy overreach.
• Respect Deadlines and Retention Rules: Implement strict tracking systems to meet the 30-day post-investigation notification window and enforce the mandatory three-year file destruction rule.

Looking Ahead

As businesses prepare for upcoming regulatory milestones—most notably the pressing obligation to have fully compliant internal regulations in place by 16 December 2026 (the focus of part three in this series)—proactive legal alignment is critical. Employers must work closely with labor and employment legal counsel, such as Marga Caproni and the team at Squire Patton Boggs, to audit existing protocols, mitigate exposure, and ensure their internal investigative frameworks can withstand rigorous judicial and regulatory scrutiny.