According to an analysis of 3,000 listings cited by RTBF, a third of the rents advertised in Brussels exceed the grid’s reference rent by more than 20%. That threshold is no longer merely indicative: since 1 May 2025, a rent above it is presumed abusive. Here is what the figures in circulation are worth, and what an agency must document.

Is the Brussels rent grid binding?

The indicative grid sets a reference rent for each home, defined by the Brussels Housing Code as the median rent shown in the grid. It takes into account location, condition, living area, number of rooms and comfort features (Article 225). It is not an automatic ceiling. But three rules give it real legal weight. The lease must state the property’s reference rent (Article 218, § 1, 4bis°). A rent more than 20% above that reference rent is presumed abusive (Article 224). Finally, since 1 May 2025, the landlord must not propose an abusive rent (Article 224/1), and the tenant may request a rent revision. For an agency drafting or negotiating a lease, the grid is therefore no longer a mere benchmark: it sets the point from which the owner must be able to justify the rent.

The presumption works both ways. Above +20%, it can be rebutted if the difference is justified by substantial comfort features intrinsic to the home or its surroundings. Conversely, a rent below that threshold is also presumed abusive if the home has substantial quality defects.

What do the figures on the gap between the grid and the market measure?

On 16 February 2026, RTBF reported that an analysis of 3,000 listings found that 34% of rents exceeded that 20% threshold. The article does not name the author of that analysis. It concerns advertised rents, not signed leases, and Hugo Périlleux notes in the same article that websites and agencies represent the upper segment of the market. The same article cites an estimate of 60,000 leases signed each year in Brussels, without giving its source.

Official figures cover a different scope: disputes. According to the 2025 activity report of Brussels Housing, the joint rental committee, operational since October 2024, received 124 requests in 2025. It issued 71 decisions. In 14 cases, the rent requested was abusive, 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. The committee found 33 rents not abusive, and 16 files reached no unanimous view. Of the 14 abusive rents, 7 conciliations were proposed and 2 succeeded. Its opinions are free and non-binding.

Why can these figures not be compared?

They do not measure the same thing. Listings show asking rents, in a rather high segment of the market. Committee files show cases challenged by tenants, so rents already perceived as high. Neither figure says what share of signed leases exceeds the grid. For a property manager, the useful conclusion is more modest: the gap exists, it is challenged in a small share of cases, and when it is, it is often wide.

What should be taken from the summer 2026 battle of figures?

In mid-June 2026, a landlords’ union published update coefficients per municipality to be added to the reference rent (RTBF, 19 June 2026). They range from +0.00% in Anderlecht to +21.55% in Woluwe-Saint-Lambert, and +20.15% in Uccle. On its members’ leases, it calculates an average actual rent of EUR 992 against a reference rent of EUR 874, a 13.5% gap (La Libre, 18 June 2026). On 23 June, RTBF reported the opposition of Badala, another landlords’ union, which considers that the initiative follows a logic that is one of the causes of the affordable housing crisis. On 9 July, RBDH replied that this grid and the Federia barometer are snapshots of particular segments of the Brussels rental market. It recalls that the rent Observatories relied on 15,000 leases, and the 2025 Federia barometer on fewer than 8,000. For an agency, one point matters more than the others. These coefficients have no legal value: only the reference rent of the official grid counts in the Article 224 calculation.

What should be documented for each rent?

The only legal ground that rebuts the presumption above +20% is substantial comfort specific to the home or its surroundings. The “market price” or the rent of neighbouring properties is not among them. The documentation to keep for each unit follows from this rule:

  • the reference rent and range taken from the grid, with the date of the simulation;
  • the comfort features that justify a gap: terrace, garden, garage, equipment, recent renovation, energy performance;
  • works invoices and the EPC;
  • the check-in inventory and dated photos.

This list does not guarantee the outcome: the court decides. It does, however, allow the agency to answer a committee request or a revision claim with documents rather than arguments.

Who decides in case of disagreement?

The tenant may refer the matter to the joint rental committee, which issues a non-binding opinion and may propose a conciliation. The tenant may also go directly to the justice of the peace, or do so after a failed conciliation. The court may revise the rent. The retroactive effect is limited: the revision takes effect at the earliest four months before the date of the court claim.

How does Seido help keep this file?

Managing several properties? Seido keeps on each unit’s record the rent charged, its history and the indexations applied, together with the lease documents. When a committee request or a revision claim arrives, the unit’s file is already assembled. See how Seido tracks deadlines and obligations under the Belgian framework.

For the Constitutional Court ruling of 17 September 2026, see our article on ruling 105/2026; for the timetable of the new grid, the one on its postponed update. On rents in agency leases, see our analysis of the 2025 Federia barometer.

Frequently asked questions

Must the reference rent appear in the lease?

Yes. Article 218, § 1, 4bis°, of the Brussels Housing Code requires the lease to state the property’s reference rent, or the range of rents around it, as shown in the indicative grid. For an agency, the simulation on the regional tool is therefore part of preparing every lease. Keeping the date and result of that simulation avoids any later dispute about the value used.

Is a rent above the grid prohibited?

No. A rent may exceed the reference rent. Above 20%, it is presumed abusive, but the landlord can rebut the presumption by proving substantial comfort features specific to the home or its surroundings. Below that threshold, the rent can still be challenged if the home has substantial quality defects. What has been prohibited since 1 May 2025 is proposing an abusive rent.

Is the joint rental committee’s opinion binding?

No. According to Brussels Housing, its opinions are free and non-binding. The committee may propose a conciliation between landlord and tenant. If it fails, or without going through it, the tenant may ask the justice of the peace to revise the rent. In 2025, the committee found 14 rents abusive out of 71 decisions, and 2 conciliations succeeded.

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.