Flood risks in France: Key Considerations

What are the main causes of flooding in France?

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Weather patterns are changing, with the seasons bringing heavier rain falls and storm surges. Indeed, the summer of 2022 recorded several incidences of storms and floods across France. This incidence combined with changes in the use of land, degradation of wetlands and expansion of permeable surface areas are increasing the likelihood of flooding in vulnerable areas. In 2020, the French government estimated that almost 17 million people in France lived in areas which were at risk of flooding due to overflowing rivers – that is, around one-quarter of the country’s population. The affected areas are not uniformly spread across France however; with 44% of the population in the South East of France categorised as at flood risk.

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Which bodies are responsible for flood protection in France?

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France has adopted a national flood risk management strategy which focuses on areas considered at highest risk, with the aim of maximising public safety, reducing the cost of damage and speeding up procedures to return to normality. Day-to-day, French municipalities – or intercommunal organisations – are responsible for flood prevention measures. The objective of this national strategy is to improve surveillance, reduce flooding risk, improve flood defences and provide a coherent approach to financing and investment. In the event of a natural disaster such as flooding, an Etat de catastrophe naturelle is triggered which enables people to claim for compensation for damage to property from insurers.

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How are flooding areas categorised in terms of planning development?

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To reduce the incidence of risk to people and damage to property, French planning authorities divide areas into three zones for determining planning and development :

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• Red Zone – No development permitted

• Blue Zone – Development permitted subject to particular conditions

• White Zone – Development permitted subject to local planning regulations

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Choosing an area to buy land or property in France necessitates thinking about many issues, of course. Below are a few questions to consider in relation to flooding risk:

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• Is the property close to any main bodies of water?

• Have there been any instances of flooding during the previous five years?

• What is the terrain like, for example the elevation, slope and orientation?

• What is the surface soil like, such as sandy, clay, chalk or limestone?

• Will extra drainage be required?

• Additional cost to insure property

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When selling a property, homeowners in France are required to notify a potential buyer that they live in a flood risk area. This information is part of the home information pack, called the dossier de diagnostics immobiliers . If you have a concern or question in relation to flooding risk, you should speak to the seller, the Notaire or the local Mairie. French Plans also has a network of experts nationwide who may be able to advise you.

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Are there any instances where planning permission may be denied as a result of a flood risk?

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It is almost always the case that project within red zones will be denied permission due to the high risk nature of the zone. If you have a construction project in a blue zone, you must respect the rules of the PPRI for your territory. The PPRI will determine the requirements for buildings in flood-prone areas. This local plan specifies the constraints that a house must meet in order to withstand a flood according to the height and speed of the water, if the construction is located in the vicinity of a watercourse. It also imposes measures to facilitate the flow of water and the draining of the building.

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The Town Planning Code requires that risks be taken into account in town planning documents. In this way, the PLU (plans locaux d'urbanisme) give the communes the possibility of accepting or refusing, under certain conditions, to issue a building permit for housing, particularly in the environment of flood zones. In order to build in a flood zone, the PPRI must make the area in question buildable. In this case, the mayor (and therefore the State) cannot refuse a building permit for that plot, even if the level of flood risk is high.

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Therefore, the fact that a plot of land is classified as being at risk of flooding by prevention plans does not, in itself, prevent the potential for new construction. It is important to understand the requirements imposed by any PPRI at the start of any project located in a flood zone; as it almost always the case that the level of detail that must be provided within any application will be more complex.

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Would you like to know more?

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If you are looking to realise your own project in France, whether it is a renovation, a new build, an extension or another project, residential or commercial – please get in touch.