Development tax: what amounts in 2026?

The development tax is a local tax collected by the municipality and the department and, only in Île-de-France, by the region. It is mainly used to finance the public facilities (networks, roads) necessary for future construction and development.

This is not an annual tax; it is only due when certain construction works are carried out.

What are the operations concerned?

The development levy applies to all operations involving the development, building, reconstruction and expansion of buildings or installations, which require a city planning authorization (building or development permit, prior declaration).

It applies as soon as a floor area (covered area bounded by walls and with a height greater than or equal to 1.80 m) is created, provided that the area exceeds 5 m². Some development projects (parking space, camping) or installations (swimming pool, wind turbine, ground-mounted photovoltaic panels, etc.) are also subject to the tax.

What rate is applied for this tax?

For a construction, the taxable value is determined by a value per m² of floor area of the project. For a development or installation, the taxable value is fixed either per unit (tent pitch, parking space, wind turbine...) or per m² of surface (swimming pool, photovoltaic panel...). On this value are applied the percentages (rates) communal, departmental and regional.

The development tax is the sum of these results.

• The annual rate of the municipal share may vary from 1% to 5%. It can be as high as 20% in some sectors.
• The annual rate of departmental share is the same for the whole department. It shall be limited to a maximum of 2,5 %.
• The regional share rate set by the Regional Council of Île-de-France may differ from one department to another within the limit of 1%.

Calculation and amount of development tax

To calculate the amount of the development tax, multiply the taxable area of the construction created by the annual value per m², then multiply this result by the rate voted by the local authority concerned by the tax.

The values per m² are updated to 1^er January of each year according to the latest construction cost index published by the National Institute of Statistics and Economic Studies (INSEE).

At 1^er January 2026, the latest construction cost index published by INSEE is that of 3^e quarter 2025, i.e. the 2056 index (index of 3^e quarter 2024: 2143).

For 2026, the values applied in the calculation of the development tax shall be as follows:

• the annual value per m² is of €892 (excluding Île-de-France) and €1,011 for municipalities located in Île-de-France;
• the standard value of swimming pools is fixed at €251 by m² ;
• the standard value of outdoor parking areas shall be €2,928 per pitch (and can go up to €5,857 per pitch upon the decision of the local authority).

Declare and pay development tax

You must declare the elements necessary for the calculation of the tax simultaneously with your property declaration, within 90 days after the completion of the work.

Go for this in your secure area on the tax website, tab "Real estate". Use the living quarters declaration form.

If the amount of your development tax is more than 1,500 €, you can pay it in 2 installments: you will receive two payment documents to be paid within 90 days and then 9 months after the completion of the work.