Do you need a city planning permit to dig a cellar?

Verified 24 February 2023 - Directorate for Legal and Administrative Information (Prime Minister)

Yes, you must obtain an authorization if the cellar has a ceiling height greater than 1.80 meters. The cellar can be an extension of your house or be buried under a plot.

Depending on its surface area, you must make a prior declaration of works or apply for a building permit in town hall. However, in certain situations, you do not need authorization.

Here are the rules to know.

Under a house

The construction of a cellar of more than 1.80 meters under ceiling increases the floor area of the existing building.

Applications for authorization vary depending on the area of the cellar and the area where your project is located.

First of all, you need to check with your city hall to find out if your project is located in a protected area.

Who shall I contact

Protected sites are remarkable heritage sites, the surroundings of historical monuments, classified or pending sites, nature reserves, the heart of national parks or a future national park.

General case

In an urban area of the PLU

Tableau - Application for city planning authorization

Increase in floor area

Approach

Less than 5 m²

No statement in town hall

Between 5 m² and 40 m²

Prior declaration of works

More than 40 m²

Building permits

Warning  

If your project is not subject to city planning authorization, however, you must follow the MORE: titleContent or the city planning document in its place.

Other situation

Tableau - Application for city planning authorization

Increase in floor area

Approach

Less than 5 m²

No statement in town hall

Between 5 m² and 20 m²

Prior declaration of works

More than 20 m²

Building permits

Warning  

If your project is not subject to city planning authorization, however, you must follow the MORE: titleContent or the city planning document in its place.

Protected area

In an urban area of the PLU

Tableau - Application for city planning authorization

Increase in floor area

Approach

Less than 5 m²

Prior declaration of works

Between 5 m² and 40 m²

Prior declaration of works

More than 40 m²

Building permits

Other situation

Tableau - Application for city planning authorization

Increase in floor area

Approach

Less than 5 m²

Prior declaration of works

Between 5 m² and 20 m²

Prior declaration of works

More than 20 m²

Building permits

Under a piece of land

The construction of a cellar of more than 1.80 meters under ceiling constitutes floor area.

Applications for authorization vary depending on the area of the cellar and the area where your project is located.

First of all, you need to check with your city hall to find out if your project is located in a protected area.

Who shall I contact

Protected sites are remarkable heritage sites, the surroundings of historical monuments, classified or pending sites, nature reserves, the heart of national parks or a future national park.

General case
Tableau - Application for city planning authorization

Increase in floor area

Approach

Less than 5 m²

No statement in town hall

Between 5 m² and 20 m²

Prior declaration of works

More than 20 m²

Building permits

Warning  

If your project is not subject to city planning authorization, however, you must follow the MORE: titleContent or the city planning document in its place.

Protected area
Tableau - Application for city planning authorization

Increase in floor area

Approach

Less than 5 m²

Prior declaration of works

Between 5 m² and 20 m²

Prior declaration of works

More than 20 m²

Building permits

Who can help me?

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