When may you start a property investigation? Suspicion, GDPR and case building

For a housing company, the power to verify follows from the Vlaamse Codex Wonen (Flemish Housing Code): the tenant must satisfy the property ownership condition throughout the entire tenancy, and the company must guarantee the allocation of its homes to those entitled to them. The justice of the peace in Hamme called investigation to that end “an essential instrument”; the justice of the peace court of Antwerp spoke of a duty in the Woonhaven case. For an OCMW, the power follows from the social investigation prescribed by the wet op het recht op maatschappelijke integratie (Act on the right to social integration), and since 2026 expressly from the federal decision that OCMWs may engage investigation firms for this purpose.

The processing of personal data that goes with this rests on a statutory task and on the legitimate interest of the landlord or the OCMW. The candidate tenant and the living wage (leefloon) applicant have also declared that their statements will be verified. All this makes investigation possible, but not unlimited.

The distinction the court makes is that between an investigation based on a concrete suspicion in a case and an investigation based on origin. The first is permitted, the second is not. The Dutch Centrale Raad van Beroep (Central Appeals Tribunal) put it sharply: an investigation may not be aimed exclusively at people with a place of birth abroad. The Belgian courts follow the same line.

Concrete indications that suffice in practice:

• long or repeated absence, established through home visits or from consumption data, especially in combination with trips to the same country each time;
• a report or statement, from the person concerned, from family, from neighbours or from another service, about a home or land abroad;
• an inheritance or a death of parents abroad that comes up in the case;
• a spending pattern, cash flows or a standard of living that do not fit the stated income;
• contradictory statements about the household situation or the residential address;
• documents that are incomplete, illegible or implausible.

What is not sufficient: nationality, country of birth, name or language. A company that has all its tenants of a certain background screened acts in a discriminatory manner and puts the evidence at risk.

The GDPR requires that no more data be processed than necessary. That argues for a stepped approach:

1. Pre-check. First only the question of whether real estate is registered in the person’s name in the country and region of the suspicion. Name, date of birth and region suffice for that. At Bureaubuitenland België, this step is usually completed within 1 to 2 weeks.
2. Full in-depth investigation only in the event of a hit: extracts, deeds, co-owners, date of acquisition.
3. Valuation only if the amount matters, for example for the living wage or for recovery.

What falls outside proportionality: observation of the person concerned, investigation into their behaviour, contacts or health, and collecting data about family members who are not in the case. That is why we work exclusively with register investigation via lawyers on site; see private detective or investigation agency.

A carefully built case file for the justice of the peace or the labour court preferably contains, in this order:

1. The sworn declaration or the living wage application, with the clause that the statement will be verified.
2. The trigger, in a short internal note with a date: which finding or report, by whom, when. This document shows that the investigation is not based on origin, which matters in the event of a defence of “discrimination”.
3. The decision to investigate, stating the stepped approach and the data processing agreement with the agency.
4. The report with the register extract, the deeds, the sworn translation and the date of consultation.
5. The hearing of the person concerned after the investigation, with their statement and any documents.
6. The calculation of the recovery and the decision, with the possibility of appeal.

Do not keep the case file longer than necessary for the proceedings and the limitation period, and share case data with us exclusively via the secure channel, never via email or the website form. See how we work and the privacy statement.

Sources: Gegevensbeschermingsautoriteit (Belgian Data Protection Authority) (GDPR); Court of Cassation 26 March 2026; Centrale Raad van Beroep, ECLI:NL:CRVB:2018:2912.