Despite the incremental development of the heritage dimension of local urban planning plans, as well as an ever more substantial relationship between immovable cultural heritage law and urban planning law, these two elements remain susceptible to raising confusion, occasionally contradicting one another frontally. The French Act of 7 July 2016 on Freedom of Creation, Architecture, and Heritage had the initial ambition of harmonizing and simplifying the mechanisms for the protection and enhancement of immovable cultural heritage, including under urban planning law. Yet the Act of 23 November 2018 on Housing Development, Urban planning, and Digital Technology has further contributed to weakening the heritage protection mechanisms and bestowed a priority on the construction of new buildings over the conservation and enhancement of old neighbourhoods and buildings.