General Data
Name of instrument Plot ratio (Coefficient d'occupation des sols - COS)
Country FR
Spatial level local
Type Spatial planning instrument
Subtype Formal planning instrument
Description Urban planning rule that defines the acceptable density of construction inside a zone of the land use plan. The COS allows the calculation of the interior floor space for buildings on the land. For example, a COS of 2.5 authorises the construction of a floor space two and a half times the land surface. The COS is fixed by the Local Urban planning document (PLU) of the commune. Certain zones of the can not present a COS. Going beyond of the COS is illegal. It is however sometimes possible, but under certain very precise conditions. Actually, one can exceed it when one lowers it by as much in another sector of the same zone of the PLU. Indeed, the law makes it possible, when one wants to protect a precise sector for quality from his landscapes, to organize a "transfer of COS", in order to gather constructions. The protected sector is then struck of inconstructibility. In suburban zone, the COS is generally about 0,3 while it exceeds 1 quickly when one approaches the center. In Paris, the COS is currently 3,25, even 3,75 in certain sectors. The project of local plan of town planning, under development, envisages to lower it to 3, with variations according to the size and the function (habitat or employment) of the piece. The rule of the "COS in fact" makes it possible to rebuild a building with identical even if its density exceeds the standard set by the COS. This rule aims at encouraging the operations of restoration on the existing buildings.
General objectives The COS makes it possible to support a true policy of land occupation, according to the objectives of the commune: a high COS will encourage with construction and thickening, while a weak COS will make it possible to maintain a space close to its natural state, and to safeguard a certain landscape quality. It can also make it possible to constitute land reserves.
General objectives keywords land development; urban development;
Responsible Local authority/Municipal council
Stakeholder Involved Planners; Entrepreneurs/businessmen; Private individuals;
Reference Urban planning code
General assessment of strength and weakness Takes part in the same idea as the legal building density limit(PLD) but the COS is more efficient, because it is given for each zone and envisages compensation possibilities inside each zone.
Date of entry 2007/03/15
Legal status mandatory for responsible body AND mandatory for end-user
Extension very frequent (> 50 % municipalities)
Comment Very frequent since the commune has set up a binging local planning document (PLU), unfrequent in other cases
Type of monitoring Qualitative / descriptive reporting
Preconditions for implementation
General comment
Status very strong direct relevance
Ranking 5
Remark -
Status municipal administration. Local economy, environmental NGOs, municipal residents, superordinate administrations
Ranking 5
Status -
Ranking 4
Remark -
Status Legislation, political will, staff
Ranking 3
Remark Staff required for supervising the implementation of the decree
Status Direction of effect, type of effect, acceptability, perpetuity
Ranking 4
Remark If effective in view of land take depends on the level of plot ratio.