France's ‘garden shed tax’ sees 2025 rise, find new rates below
Completed property extensions and new constructions have to be declared to your mairie within 90 days
The tax is often higher in departments close to the capital
M Gl / Shutterstock
A tax paid on certain property improvements including building swimming pools, verandas, house extensions, and garden sheds in France has increased this year.
In addition to the potential for increased property tax (taxe foncière) on homes due to increased value, extensions and new amenities may be subject to a separate one-off construction tax.
This is known as the taxe d’aménagement, sometimes called a garden shed tax.
What is the tax?
It applies to property extensions and constructions that require building permission, either through a permis de construire, permis d'aménager or déclaration préalable de travaux and that reach a certain size.
Extensions/constructions that are at least 5m² in size, and are enclosed with a ceiling height of 1.80m or more, are subject to the tax.
This includes almost all extensions to a main property (additional room, conservatory etc) as well as many garden sheds – hence the nickname for the tax.
Certain other constructions, including swimming pools, wind turbine installations and some carports are also subject to the tax.
The tax is calculated by multiplying the surface area in square metres by a fixed value figure, or in certain cases via a standard rate for each object installed (wind turbines, parking spaces, etc).
The tax is then the sum of this figure multiplied by the rate set by the local commune; and this figure multiplied by the rate set by the department.
The rate set by the commune is usually between 1% and 5% (exceptionally, more in certain cases where constructions will involve significant additional investment in local infrastructure).
The rate set by the department is usually between 1% and 2.5%.
The exception is in Île-de-France, where the region also levies an additional amount, up to a maximum of 1%.
What are new increases?
The latest increases in the tax are tied to inflation calculations from national statistics body Insee and relate to the fixed values used.
The fixed values in place since January 2025 are:
€930 per m² (up from €914 in 2024, €886 in 2023 and €820 in 2022)
€1,054 per m² for constructions in Île-de-France (€1,036 in 2024, €1,004 in 2023 and €929 in 2022)
For swimming pools, the average price is €262 per m² (up from €250 in 2024)
Increases for other specific constructions can be found on the Service Public help site here (available in English and French).
Some communes also offer full or partial exceptions for the tax on certain installations.
Your mairie should be able to inform you when you are applying for building permission if your construction will be eligible for these exemptions.
How is the tax paid?
Declarations of completed constructions have to be made within 90 days to the local authorities.
The official Service public site states the preferred method to declare a completed improvement is now via the biens immobiliers section of your personal space on the French tax site.
If in doubt your tax office or mairie will be able to advise you on submitting the declaration another way.
The bill for the tax will be sent out once the declaration is complete.
If the overall tax is less than €1,500, a one-off payment will be required.
If the bill is more than this, you will receive one bill three months after completion of the work, and one nine months after.
The bill will inform you of how to pay the tax.
Local tax authorities are now using AI to catch undeclared extensions, reaping hundreds of millions of euros in unpaid taxes, including the taxe d’aménagement.
Read more: French authorities use AI to help recoup €200 million in unpaid tax from one department alone
