A private individual owning ten apartments, with no company number, renting to ordinary tenants. Nothing illegal. But are they a "professional" under the Belgian Code of Economic Law? The answer, now confirmed by recent case law, can render several standard lease clauses void.
The concept of "enterprise" in the Code of Economic Law
The Belgian Code of Economic Law (CEL) does not reserve the status of enterprise for commercial companies or registered self-employed persons alone. It sets a functional definition, based on actual economic behaviour.
Article I.8 of the CEL, read together with articles I.1,1° and I.22/1,4°, defines an enterprise as "any natural or legal person pursuing an economic purpose on a durable basis". Two cumulative elements: an economic activity, and a durable character.
A private individual who regularly lets several properties, receiving rental income, may therefore meet this definition, even without a company registration number, even without ever having created a company. The absence of formal registration does not prevent the qualification.
On the other side, a tenant renting a home generally falls within the definition of "consumer" under article I.1,2° of the CEL: a natural person acting for purposes outside their professional activity.
Once both conditions are met, landlord-as-enterprise and tenant-as-consumer, Book VI of the CEL (unfair terms, articles VI.82 to VI.84) and Book XIX (debt recovery from consumers) apply on top of the regional residential tenancy rules.
What recent case law says
The theoretical uncertainty has been resolved in practice. The Court of First Instance of Hainaut, Charleroi division, in a ruling of 11 September 2025, found that a landlord owning around ten apartments qualified as an enterprise, regardless of having no company registration number.
The reasoning is straightforward: the duration of the letting activity and the volume of properties managed demonstrate a durable pursuit of an economic purpose. The legal form chosen (natural person) is irrelevant.
For profit-making companies, the question does not even arise: they are enterprises by definition, without any volume or duration requirement.
The concrete consequences for lease clauses
This is where the topic becomes operational. Several clauses commonly found in standard leases change radically in legal scope depending on whether the landlord qualifies as an enterprise.
The unilateral penalty clause: void by operation of law
The unilateral penalty clause, one that provides for a lump sum payable by the tenant alone without an equivalent obligation on the landlord, is expressly listed in article VI.83,17° of the CEL. It appears among the clauses deemed unfair in all circumstances when included in a contract between an enterprise and a consumer.
The sanction is nullity. The landlord who thought they had secured a termination indemnity through this clause loses it entirely, with no possibility of salvage. It must be replaced by a reciprocal clause, binding on both parties, in balanced proportions.
Late-payment interest: capped at the 2002 legal rate
A lease may provide for late-payment interest on unpaid rent. Once the landlord is an enterprise and the tenant a consumer, Book XIX of the CEL applies. Article XIX.4,1° states that the late-payment interest rate may not exceed the rate set by the Act of 2 August 2002 on combating late payment in commercial transactions.
Any contractual clause setting a higher rate is deemed unwritten. For the first half of 2026, this rate is 10.5%. A lease providing for 12% or 15% late-payment interest is stripped of that clause, which falls automatically.
Lump-sum indemnities: graduated caps
Book XIX of the CEL also introduces a cap regime for lump-sum indemnities, regardless of their contractual label (collection fee, penalty indemnity, etc.). The maximum amounts are as follows:
- €20 if the amount due is €150 or less
- €30 + 10% of the bracket between €150.01 and €500 for debts in that range
- €65 + 5% of the portion above €500, with an absolute ceiling of €2,000 when the outstanding balance exceeds €500
These caps apply to the amount claimed for indemnification or debt recovery, regardless of what the lease provides. Any clause more favourable to the landlord is deemed unwritten.
Sanctions for non-compliance
The consequences are not limited to the nullity of the offending clauses. Failure to comply with Book XIX of the CEL exposes to criminal sanctions of level 2, as defined in Book XV of the same Code.
These sanctions include a fine calculated on the basis of €26 multiplied by 4% of annual turnover, with a floor of €10,000. For a landlord collecting several hundred thousand euros in annual rent, the exposure is significant.
This is not a theoretical risk. The increase in consumer claims before justices of the peace and courts of appeal, combined with the growth of tenant advocacy organisations, has raised the probability that a landlord who is a "professional" in practice will face these provisions.
The grey area: how to know whether you are affected
There is no clear statutory quantitative threshold. The law does not set a figure: "from X apartments onwards, you are an enterprise". The qualification results from an overall assessment of the circumstances: number of properties, regularity of income, organisational structure, duration of activity.
The Charleroi ruling of 11 September 2025 applied the qualification to a landlord owning around ten apartments. That empirical level is not a statutory rule, but it gives an indication of the threshold at which courts pay attention.
Below that level, the qualification remains possible if other elements show a structured approach: use of a professional property manager, dedicated accounting, regular property acquisitions, etc.
Prudence therefore suggests auditing lease clauses whenever multiple properties are managed on a regular basis, regardless of the legal form chosen.
What this means for a property management portfolio
For a letting agency or independent property manager handling properties on behalf of third-party landlords, the situation is twofold.
On one hand, the agency itself is an enterprise under the CEL. On the other, the landlords whose properties it manages may also qualify. The manager therefore has an interest in alerting multi-property owner clients to this risk, and in ensuring that the leases it drafts or uses comply with CEL requirements.
This is precisely where a tool like SEIDO delivers concrete value: lease templates are kept current with legislative and case law developments, the clause library includes only CEL-compliant provisions (reciprocal penalty clauses, interest capped at the legal rate, indemnities within the regulatory brackets), and the calculation of indemnities and interest is done automatically at the correct cap. Across a portfolio of dozens or hundreds of units, documentary standardisation is both a time-saver and a legal safeguard.
What to do if your current leases contain non-compliant clauses
The priority is an audit. Check clause by clause whether the current lease contains a unilateral penalty clause, an interest rate above 10.5%, or lump-sum indemnities without a cap.
Then, on renewal or when signing a new lease, correct those clauses. A unilateral penalty clause can be replaced by a symmetrical clause. An interest rate that is too high can be brought back to the legal rate. Indemnities can be reformulated within the Book XIX limits.
For leases already in force, the nullity of non-compliant clauses does not affect the lease itself. Only the offending clause falls. The rest of the contract remains valid.
Finally, vigilance is also needed before any dispute: it is better to correct a clause before a tenant challenges it in court than to discover its nullity during proceedings.
Sources and references
- Code of Economic Law, art. I.8, I.1,1° and 2°, I.22/1,4° (definitions of enterprise/consumer)
- Code of Economic Law, Book VI, art. VI.82 to VI.84, including art. VI.83,17° (unilateral penalty clause as unfair term)
- Code of Economic Law, Book XIX, art. XIX.4,1° (late-payment interest cap) and art. XIX.4 (lump-sum indemnity caps)
- Code of Economic Law, Book XV (criminal sanctions level 2)
- Act of 2 August 2002 on combating late payment in commercial transactions (reference rate: 10.5% in H1 2026)
- Civil Code, art. 5.52 (law of obligations)
- Court of First Instance of Hainaut, Charleroi division, ruling of 11 September 2025 (enterprise status of a multi-unit landlord without company registration)