« Reversible construction today so as to destroy less tomorrow seems to be an obvious choice, that of environmentally sustainable construction. » « Thinking in terms of reversibility means anticipating the evolution of a building even before its construction to simplify as much as possible the adaptations and their costs during its transformation. » Les 101 mots d’initiative logement à l’usage de tous, Collectif, Collection 101 mots, Archibooks.

Recently, the local urban planning program regulations have made it possible to specify a variety of purposes in a building (Town planning code, art. R. 151-37). Multifunctionality is essential in the context of local policies.

On the other hand, the law on urban planning permits has not yet taken into account these developments.

Ideally, a building with a reversible design should no longer require any further authorization after the one originally granted. If one has to be requested each time a building is modified, this will, by definition, result in a loss of time and legal uncertainty.

Rather than an undesignated construction, a new type of building could be considered, which would have a dual purpose. In the current state of substantive law, this is not possible, but it could clearly be addressed as part of a legislative process.