Retrofitting, densification and nature-based solutions in Paris and Orléans: Stakeholder scenario mapping (ReHousIn Deliverable 5.2, France)

This empirical report presents the results of three stakeholder scenario-mapping workshops held in June 2026 in Paris and Orléans as part of the Horizon Europe project ReHousIn (Deliverable 5.2). For the interpretive synthesis of the French case and its European comparison, see Cremaschi, Guironnet, Rotondo and Vitale (2026), doi:10.31235/osf.io/ynkcr_v1.The workshops brought together municipal and metropolitan administrations, public development agencies, social housing providers, private developers and housing support organisations to examine the distributive effects of three green housing interventions: housing retrofitting combined with nature-based solutions in Paris and in Orléans, and densification through land recycling in the Paris region. For each case, the report reconstructs the key impacts, the mechanisms that explain them and the variations across scenarios, then outlines pathways towards just futures, with their levers and trade-offs.Findings show that energy savings from retrofitting are modest and unevenly shared: social housing tenants benefit most, while low-income owner-occupiers in condominiums face upfront costs with payback periods of 20 to 30 years, longer than their expected tenure, which can push them to sell. Densification generates amenities but mainly raises property values, with gains captured by surrounding owners and displacement risks for private tenants. In Orléans, one-for-one demolition rules have led to de-densification. The report identifies policy levers (rent regulation, deferred-repayment advances for low-income owners, public land control, developer charters, regulatory stability) and two non-negotiable principles: no displacement of lower-income residents because of works, and no rise in housing costs without support for vulnerable households.