On 17 September 2026, in judgment no. 105/2026, the Constitutional Court dismissed the real estate federations’ action against the entry into force of the ban on abusive rents in Brussels. It did so without examining the merits: for an agency re-letting a property, the rules applied since 1 May 2025 therefore remain in place, and a file justifying the rent remains the best protection.

What did the action dismissed on 17 September target?

The action was brought on 23 October 2025 by seven parties: the Union professionnelle du secteur immobilier (UPSI), Embuild, the Confederatie van Immobiliënberoepen Vlaanderen (CIB), a landlords’ union, Federia and two owners. It targeted the Brussels ordinance of 10 April 2025, published in the Belgian Official Gazette on 30 April 2025. That text sets 1 May 2025 as the entry into force of Articles 8 to 13 of the ordinance of 28 October 2021, which introduces a joint rental committee and combats abusive rents. Ten associations intervened on the tenants’ side, including RBDH, the Syndicat des Locataires and Badala. The hearing took place on 1 July 2026, at the applicants’ request. Judgment no. 105/2026 (docket 8569) was delivered on 17 September 2026. Its operative part is a single sentence: the Court dismisses the action.

Why did the Court not rule on the merits?

The Court set the action aside for two procedural reasons, without ruling on the right to property. First, it declared itself without jurisdiction over the grid. The applicants considered the grid neither reliable nor representative of market prices. For the Court, this criticism in fact targets the order of 19 October 2017 that governs the grid, amended in 2022. A Government order falls outside its review (point B.10). Second, the other complaints concerned the scope of the ban and the lack of clarity of the notions of “substantial comfort features” and “substantial quality defects”. They are in fact directed against the 2021 ordinance itself, which the 2025 text did not amend. As the six-month deadline to challenge that ordinance had expired, these complaints are inadmissible ratione temporis (point B.11). The judgment therefore neither validates nor condemns the grid: it leaves the system as it has operated since May 2025.

What remains in force for your re-lettings?

Three rules of the Brussels Housing Code continue to apply to every new residential lease. The lease must state the reference rent of the property, or the range of rents around it (Article 218, § 1, 4bis°). The rent is presumed abusive when it exceeds its reference rent by twenty percent. The presumption falls if the gap is justified by substantial comfort features intrinsic to the home or its surroundings (Article 224). Finally, since 1 May 2025, the landlord must not propose an abusive rent. Otherwise, the tenant may request a revision (Article 224/1). The tenant can go to the joint rental committee, whose opinion is not binding, or to the justice of the peace. The revision takes effect at the earliest four months before the court claim. For the agency, the practical consequence is simple: every Brussels re-letting starts with a simulation of the reference rent, and every rent more than 20% above it must rest on a file.

What does the Region say after the judgment?

On the Region’s side, the Secretary of State for Housing, Karine Lalieux, welcomed a decision that secures an essential tool to better protect tenants, according to L’Avenir. Speaking to RTBF, she announced an update in two stages, with several months of work and an updated grid expected within two years. On 22 September, on BX1, she added that the grid must be reviewed with new elements and that a rent observatory should be launched. BX1 writes that the grid should be revised in the course of 2027, after a first report from that observatory.

Can the debate return to the Court?

Yes, through a preliminary question. When a question on the constitutionality of an ordinance is raised before a court, that court must in principle refer it to the Constitutional Court (Special Act of 6 January 1989 on the Constitutional Court, Article 26). Owners and tenants can thus ask for a preliminary question to be referred to the Court. This is the route two justices of the peace took for the winter moratorium, decided by judgment no. 131/2025, which we analyse in our article on the winter moratorium before the Constitutional Court.

What do the joint rental committee’s figures show?

The 2025 activity report of Brussels Housing measures the system over its first full year. The joint rental committee, operational since October 2024, received 124 requests in 2025 and issued 71 decisions. It found the rent abusive in 14 cases, that is 11% of requests and 20% of decisions. In those 14 files, the average actual rent was EUR 1,697 against an average reference rent of EUR 1,147, a 48% gap. In their press release, the federations put forward a figure of 22% of rents found abusive; it does not exactly match the report’s counts. For an agency, these figures give a useful order of magnitude. Files that end with a finding of abuse involve, on average, large gaps, well beyond the 20% threshold. The committee also found 33 rents not abusive, and 16 files reached no unanimous view.

Our article on the gap between the grid and the market details these figures and compares them with listing analyses.

What checklist justifies a rent more than 20% above the grid?

The only legal ground that rebuts the presumption is substantial comfort specific to the home or its surroundings. The justification therefore consists of documents, not market arguments:

  1. The reference rent simulation, dated, with the range used and the characteristics entered: floor area, number of bedrooms, condition, EPC.
  2. The list of comfort features that explain the gap: terrace, garden, garage, lift, kitchen and bathroom equipment, insulation.
  3. Evidence of these features: works invoices, EPC, dated photos, floor plan.
  4. The check-in inventory, which records the actual condition of the home at the start of the lease.
  5. The reference rent stated in the lease, as required by Article 218, § 1, 4bis°.

This list does not guarantee the outcome, since the committee and the court assess each case. It does, however, avoid having to rebuild a file after the fact, once the tenant has already filed a request. For the timetable of the grid update, see our article on the postponed update.

How does Seido help keep this justification?

Managing several properties? Seido keeps on each unit’s record the rent charged, its history and the indexations applied, together with the lease documents. The documents that justify a rent stay attached to the unit, rather than scattered across mailboxes. See how Seido tracks deadlines and obligations under the Belgian framework.

Frequently asked questions

Does judgment 105/2026 make the rent grid more binding?

No. The judgment changes no rule. It dismisses an action that could have annulled the entry into force of the ban on abusive rents. The grid’s legal weight remains the one set by the Brussels Housing Code since 1 May 2025: reference rent mandatory in the lease, presumption of abuse above 20%, revision possible at the tenant’s request. The Court did not rule on the reliability of the grid itself.

Should leases signed since May 2025 be reviewed?

Not because of the judgment, which changes nothing in the applicable law. However, a lease signed since May 2025 at a rent more than 20% above the reference rent may be subject to a revision request. Checking that each of these leases states the reference rent and has a justification file remains good practice, especially for the properties furthest from the grid.

When will the new grid take effect?

No date has been set. On 17 September 2026, Karine Lalieux announced an updated grid within two years, in two stages. BX1 mentions a revision in the course of 2027, after a first report from a rent observatory. Until then, the current grid remains the only legal reference for Brussels leases.

Can an owner challenge the grid before a justice of the peace?

A justice of the peace hearing a rental dispute can refer a preliminary question on the system to the Constitutional Court (Special Act of 6 January 1989 on the Constitutional Court, Article 26). This requires an individual dispute in progress, for example a rent revision request. The court assesses whether the question must be referred: the law provides for exceptions. For an agency, this is not a management strategy, but it is worth knowing if a client wants to go to court.

Sources and references

Last updated: September 2026. This article is provided for information purposes only and does not constitute legal advice. For any specific situation, consult a real estate law professional.