Residential Lease Agreements: The Court of Cassation and the Readjustment to Congruity of Rent for Written but Unregistered Contracts (Order No. 15891/2025)

The landscape of residential lease agreements has always been a fertile ground for debates and disputes, given its importance for both landlords and tenants. The legislation, particularly Law No. 431 of 1998, aims to balance the needs of both parties, but the practical application of its provisions can often generate uncertainty. In this context, the intervention of the Court of Cassation is fundamental to provide clarity and guidance. Order No. 15891 of June 13, 2025, falls precisely within this framework, offering a decisive interpretation regarding written but unregistered residential lease agreements.

The Regulatory Framework: Law 431/1998 and its Evolutions

Law No. 431 of December 9, 1998, is the cornerstone of the regulation of residential leases in Italy. It introduces two main contractual models: free-rent contracts (Art. 2, paragraph 1) and agreed-rent contracts (Art. 2, paragraph 3), the latter defined by territorial agreements between landlord and tenant associations. A crucial aspect of this law is the obligation to register lease agreements, a formality that, if neglected, can have significant consequences on the validity and effectiveness of the contract itself. Over the years, the legislator has intervened multiple times to combat the phenomenon of "under-the-table" or irregular rentals, introducing mechanisms aimed at protecting the weaker party in the relationship, often the tenant.

Order 15891/2025: The Case and the Principles Affirmed

The recent Order No. 15891 of 2025, issued by the Third Civil Section of the Court of Cassation, with President R. G. A. Frasca and Rapporteur M. Rossetti, addressed the appeal filed by S. (C. L.) against N. (N. F.), quashing with referral a previous decision of the Court of Appeal of Turin of March 3, 2021. The core of the issue concerns the so-called "readjustment to congruity" of the rent for residential lease agreements that, although drawn up in writing and not simulated, have not been registered.

A free-rent residential lease agreement, unregistered but concluded in writing and not simulated, is subject to the "readjustment to congruity" provided for by Art. 13, paragraph 6, third and fourth periods, of Law No. 431 of 1998, even if stipulated before January 1, 2016, but only from that date onwards; in such a case, the judge, when determining the rent due, cannot exceed the amount agreed upon by the category associations, pursuant to Art. 2, paragraph 3, of the same law, with the sole exception of cases where the freely agreed rent is lower than the latter, and this applies both to free-rent contracts and to agreed-rent contracts, as the aforementioned fourth period of paragraph 6 of Art. 13, in establishing the judge's redetermination powers, merely refers to Art. 2 without distinction of paragraphs, thus encompassing both paragraph 1 (free-rent contracts) and paragraph 3 (agreed-rent contracts) of that provision.

This ruling by the Court of Cassation is of fundamental importance. It establishes that a residential lease agreement, even if free-rent, if drawn up in writing but not registered and not simulated, is still subject to the mechanism of "readjustment to congruity" of the rent. This means that the rent can be judicially redetermined. A crucial point is the applicability of this rule even to contracts stipulated before January 1, 2016, but with effect only from that date. Furthermore, the judgment clarifies a significant limit for the judge: in redetermining the rent, they can never exceed the amount agreed upon by the category associations, as provided for by Art. 2, paragraph 3, of Law 431/1998. The only exception occurs if the freely agreed rent was already lower than this threshold. This rule applies to both free-rent and agreed-rent contracts, emphasizing the centrality of the parameters established by territorial agreements.

Practical Implications of the Decision

The Court of Cassation's Order has a significant impact on landlords and tenants, introducing greater clarity and, at the same time, outlining precise responsibilities and protections.

• For Landlords: Even in the presence of a written contract, failure to register exposes them to the risk of judicial redetermination of the rent, which, however, cannot exceed the values of territorial agreements. This reinforces the importance of tax compliance through registration.
• For Tenants: The decision offers concrete protection. If a written but unregistered contract is in place, it is possible to request the judge to readjust the rent to fair values, based on agreed rents, even if the contract was stipulated years ago (before 2016), with effect from 2016.
• The Role of Agreed Rents: The ruling highlights how agreed rents, defined by agreements between category associations, represent an essential reference parameter for the "congruity" of the rent, both for free-rent contracts and for agreed-rent contracts.

Conclusions: Legal Certainty and Protection of Parties

Order No. 15891 of 2025 by the Court of Cassation represents an important piece in the mosaic of case law regarding residential leases. It consolidates the principle of "readjustment to congruity" of rent for written but unregistered contracts, extending its application to past situations and setting a clear limit on contractual autonomy in cases of formal non-compliance. The decision reiterates the legislator's and jurisprudence's intention to ensure greater transparency and protection, particularly for tenants, by discouraging evasive practices and promoting the regularity of lease relationships. For landlords and tenants, fully understanding these dynamics is essential for managing their rights and duties effectively, often making the support of a legal professional indispensable.