The Observatory for the Prevention of Building Deterioration in Paris

November 2020, last updated 02 April 2021
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Each year, this Observatory enables a list to be drawn up of private residential buildings in Paris that run the greatest risk of becoming run down.

Aerial view of residential buildings, Paris 9th district © Apur

Created in 2008 by Apur, the aim of The Observatory for the Prevention of Building Deterioration in Paris is to proactively identify private residential buildings facing difficulties, in order to prevent them from deteriorating and becoming insalubrious.

In order to carry out this monitoring process, the Observatory centralises data files on all private residential buildings in Paris built before 2000 and examines 10 fragility indicators:

  • A dense concentration of small rented accommodation,
  • Formal notices under the construction and housing code (CCH) particularly articles on general emergency policies,and any type of danger or insecurity linked to equipment.
  • Formal notice under the Departmental Health Regulations,
  • A positive lead diagnosis in any communal or private part of a building,
  • A significant percentage of social housing applicants among residents of a building, 
  • Unpaid communal water bills in a building.
  • Former furnished hotels.
  • Presence of termites.
  • Several interventions by the fire-brigade,
  • Indebtedness of co-owners and the condominium. 

The cross-referencing of files and weighting of indicators enables a list to be drawn up of the buildings presumed to be the most “at risk” of becoming degraded.


The Observatory monitors private residential buildings in Paris. It endeavours to identify the various types of problems linked to a building’s technical characteristics, its management and occupation. Each year it produces a list of private buildings “to be monitored” in view of preventative action being taken. The identification of these buildings thus aims to guide a part of the field inspections carried out by the Technical Services of the City of Paris Housing Department.
In this way it contributes to guiding field inspections carried out by Technical Services, encouraging an administrative intervention at the earliest possible stage. This proactive approach aims to prevent any buildings from falling into disrepair and the downward spiral towards insalubrity. 

How it works

The Observatory is a partnership tool formed between the City of Paris (Department of Housing and Accommodation), the State (DRHIL, Police Prefecture) and Apur, which is responsible for running it and centralising the partners’ data files. 

In return, the Observatory provides information so that services in charge of housing in Paris and more specifically the Technical Service of the City of Paris Housing Department can carry out measures to prevent housing from deteriorating. Each year between 150 and 300 buildings “to be monitored” are reported to the City of Paris.