Towards facilitating the conversion of offices and other buildings into housing
Designed to respond to the “urgent need to protect against a housing shortage“[1], Law no. 2025-541 enacted on June 16, 2025, mobilises several urban planning tools to encourage the conversion of existing buildings into housing.
One of the main contributions of the law is the establishment of a “reversible” building permit, “inspired by the dual-status permit created by Law no. 2018-202 of March 26, 2018 on the 2024 Paris Olympic Games“[2].
Thus, the competent authority for town planning plan (plan local d’urbanisme – PLU) can now delimit areas in which the building permit may authorise several successive uses (destinations) of the building[3], without it being necessary for any of these uses to be residential.
In operational terms, and subject to the decree to be issued:
- the building permit shall expressly mention (i) the various authorised uses and, (ii) at the request of the competent authority for planning permission, the initial use of the building;
- the rules on extension and expiry of the validity period of the building permit shall apply to works authorised in respect of the initial state of the construction. As a result, with regard to the initial state, the works must in principle be undertaken within three years of the building permit being issued[4] – a period which may be extended twice for one year[5] – and, after this period, may not be interrupted for more than one year;
- regarding the subsequent stages of construction, the administrative formalities required to move from one stage to another vary according to the degree of precision of the initial building permit application:
- if the initial application allows the competent authority to verify the compliance of the subsequent stages of the project with the rules applicable at the time of its issuance, the building permit – valid for 20 years – authorises these stages in advance. In this case, the owner must simply inform the mayor and, where applicable, the competent authority for planning permission of any change of use or status at least three months before the actual change of use;
- conversely, if the initial application does not make it possible to ensure the compliance of the subsequent stages of the project, a new application for planning permission “necessary for the completion of the works related to the change of use“[6] must be submitted;
- in order to give full effect to the reversible building permit and to secure the subsequent stages of the building, subsequent amendments to the PLU rules relating to use shall not affect the validity of the building permit for a period of 20 years from its issuance.
The implementing decree could, in particular, determine the content of the application for a reversible building permit and the procedures for its examination, in relation to the subsequent stages of the project. For example, it could be usefully confirmed that all authorisations or formalities necessary for all future stages (establishments open to the public, prefectoral approval (agrément), request for case-by-case examination (examen au cas par cas), etc.) must be requested or completed at the time of the initial application for a building permit.
The law dated June 16, 2025 also introduces a derogation from the provisions of the PLU relating to the use of buildings.
The competent authority may now authorise, by way of derogation from the said PLU rules, a change of use of a building other than residential to a building used primarily for residential purposes. This derogation may also apply to works and extension or elevation works subject to the planning permission.
The new Article L. 152-6-5 of the Town Planning Code defines the conditions under which such a derogation may be granted. In particular:
- the competent authority must take into account “the nature and location of the project“;
- the approval of the competent authority for the PLU must be obtained;
- the opinion of the mayor must be obtained when he is not competent to issue the planning permission.
This exemption may only be refused on the grounds of:
- the risk of nuisance to future inhabitants or residents;
- insufficient accessibility by public transport;
- the impact of the project on school demographics or on social and functional diversity objectives.
The law aimed at facilitating the conversion of offices and other buildings into housing also extends the scope of the “main residence” easement established by the Le Meur Law dated November 19, 2024 (no. 2024-1039): the regulations of the PLU may thus define areas in which housing resulting from the conversion of buildings intended for non-residential use must be used exclusively as main residences.
With regard to the conventional financing arrangements for public facilities (équipements publics), it should be noted that the scope of the urban partnership project (projet urbain partenarial – PUP) now covers the facilities necessary for the conversion of buildings used for purposes other than residential into buildings used primarily for residential purposes[7].
Finally, in order to facilitate the creation of university residences, CROUS (Centres Régionaux des Œuvres Universitaires et Scolaires) can unconditionally use design-build contracts (marchés de conception-réalisation) for the construction of rental housing subsidised by the State, financed with public aid[8]. Similarly, the PLU regulations may now designate areas within which university residences benefit from an increase in the buildable volume resulting from rules relating to building size, height and footprint[9].
While the law enacted on June 16, 2025 introduces new tools that are eagerly awaited in practice, these major changes have yet to be fully implemented by local authorities. For example, the issuance of reversible building permits necessarily requires that the authority responsible for the PLU has first defined the areas in which such permits may be issued.
The future of this law will therefore largely depend on its appropriation at the local level by public authorities.