Do I need city planning permission to build a mezzanine or an additional floor?
Verified 05 December 2025 - Public Service / Directorate of Legal and Administrative Information (Prime Minister)
To build a mezzanine or a additional floor of a ceiling height greater than 1.80 m and a floor area greater than 5 m², you have to file in town hall advance notification (RFP). From 20 m² or 40 m² in an urban area of a MORE: titleContent, you must file a building permit (PC). However, up to 5 m², you are exempt from formality. We present the regulations to you.
Warning
Whatever your project, if it is accompanied by a changing the appearance of the exterior of the building (for example, laying of a roof window), it is still subject to city planning authorization.
In any case, you must consult the PLU of your municipality which may provide for special rules. To know these rules, you must contact the city planning department of your town hall.
If your project leads to a view in your neighbor, you must also respect distance rules in relation to the limits of his property.
One RFP or a PC is necessary depending on whether your project is located in a protected area or outside. You can obtain this information from your town hall.
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General case
The type of city planning permission depends on the area where your project is located:
In an urban area of a PLU
The type of city planning authorization depends on the floor area of your project:
Mezzanine or additional floor up to 5 m²
The creation of a mezzanine or an additional floor up to 5 m² of floor area is exempt from city planning formality.
Mezzanine or additional floor greater than 5 m² up to 40 m²
The creation of a mezzanine or an additional floor with a floor area greater than 5 m² up to 40 m² is subject to DP. This is the case provided that the creation of floor area does not lead the total area of the construction to exceed the following thresholds:
- 150 m² of floor space for non-agricultural construction (e.g. house, house, business, warehouse)
- 800 m² of floor space for agricultural construction.
In case of overshooting, a PC request is required beyond 20 m² of floor area created. The recourse to the architect is mandatory to develop the plans for the file.
Depending on whether your project is located in Paris or in another municipality, the application must be submitted:
- By dematerialized means according to the provisions taken by the commune (consult the website of the town hall or inquire on the spot)
- Per letter RAR: titleContent
- In person against receipt signed by the town hall.
You must complete and submit your RFP file by dematerialized means according to the arrangements made by your municipality or on a paper form.
Ask on the website of the town hall or on site.
You can complete and submit your RFP application on the Internet:
You can complete your RFP application using a form:
Prior declaration of constructions and works not subject to building permits
You must submit your file to the Reception and User Service Office (Basu: titleContent) only by dematerialization:
Reception and user service office (Basu) in Paris: one-stop shop
Depending on whether your project is located in Paris or in another municipality, the application must be submitted:
- By dematerialized means according to the provisions taken by the commune (consult the website of the town hall or inquire on the spot)
- Per letter RAR: titleContent
- In person against receipt signed by the town hall.
You must complete and submit your PC file by dematerialized means according to the arrangements made by your municipality or on a paper form.
Ask on the website of the town hall or on site.
You can complete and submit your PC file on the internet:
The CP form varies depending on whether the project involves a single-family home or another type of building:
You can complete your PC application using a form:
Application for a building permit for a detached house and/or its annexes (PCMI)
You can complete your PC application using a form:
Application for a building permit (other than for a detached house or its annexes)
You must submit your file to the Reception and User Service Office (Basu: titleContent) only by dematerialization:
Reception and user service office (Basu) in Paris: one-stop shop
Mezzanine or additional floor of more than 40 m²
The creation of a mezzanine or an additional floor with a floor area greater than 40 m² is subject to PC.
Depending on the surface of your house before or after the work, the use of an architect may be required to file the building permit.
Depending on whether the project is located in Paris or in another municipality, the application must be submitted:
- By dematerialized means according to the provisions taken by the commune (consult the website of the town hall or inquire on the spot)
- Per letter RAR: titleContent
- In person against receipt signed by the town hall.
You must complete and submit your PC file by dematerialized means according to the arrangements made by your municipality or on a paper form.
Ask on the website of the town hall or on site.
You can complete and submit your PC file on the internet:
The CP form varies depending on whether the project involves a single-family home or another type of building:
You can complete your PC application using a form:
Application for a building permit for a detached house and/or its annexes (PCMI)
You can complete your PC application using a form:
Application for a building permit (other than for a detached house or its annexes)
You must submit your file to the Reception and User Service Office (Basu: titleContent) only by dematerialization:
Reception and user service office (Basu) in Paris: one-stop shop
Outside an urban area of a PLU
The type of city planning authorization depends on the floor area of your project:
Mezzanine or additional floor up to 5 m²
The creation of a mezzanine or an additional floor up to 5 m² of floor area is exempt from city planning formality.
Mezzanine or upper additional floor 5 m² up to 20 m²
The creation of a mezzanine or an additional floor with a floor area greater than 5 m² up to 20 m² is subject to DP.
Depending on whether your project is located in Paris or in another municipality, the application must be submitted:
- By dematerialized means according to the provisions taken by the commune (consult the website of the town hall or inquire on the spot)
- Per letter RAR: titleContent
- In person against receipt signed by the town hall.
Depending on whether your project is located in Paris or in another municipality, the application must be submitted:
- By dematerialized means according to the provisions taken by the commune (consult the website of the town hall or inquire on the spot)
- Per letter RAR: titleContent
- In person against receipt signed by the town hall.
You must complete and submit your RFP file by dematerialized means according to the arrangements made by your municipality or on a paper form.
Ask on the website of the town hall or on site.
You can complete and submit your RFP application on the Internet:
You can complete your RFP application using a form:
Prior declaration of constructions and works not subject to building permits
You must submit your file to the Reception and User Service Office (Basu: titleContent) only by dematerialization:
Reception and user service office (Basu) in Paris: one-stop shop
Depending on whether your project is located in Paris or in another municipality, the application must be submitted:
- By dematerialized means according to the provisions taken by the commune (consult the website of the town hall or inquire on the spot)
- Per letter RAR: titleContent
- In person against receipt signed by the town hall.
You must complete and submit your PC file by dematerialized means according to the arrangements made by your municipality or on a paper form.
Ask on the website of the town hall or on site.
You can complete and submit your PC file on the internet:
The CP form varies depending on whether the project involves a single-family home or another type of building:
You can complete your PC application using a form:
Application for a building permit for a detached house and/or its annexes (PCMI)
You can complete your PC application using a form:
Application for a building permit (other than for a detached house or its annexes)
You must submit your file to the Reception and User Service Office (Basu: titleContent) only by dematerialization:
Reception and user service office (Basu) in Paris: one-stop shop
Mezzanine or additional floor of more than 20 m²
The creation of a mezzanine or an additional floor with a floor area greater than 20 m² is subject to PC.
Depending on the surface of your house before or after the work, the use of an architect may be required to file the building permit.
Depending on whether your project is located in Paris or in another municipality, the application must be submitted:
- By dematerialized means according to the provisions taken by the commune (consult the website of the town hall or inquire on the spot)
- Per letter RAR: titleContent
- In person against receipt signed by the town hall.
You must complete and submit your PC file by dematerialized means according to the arrangements made by your municipality or on a paper form.
Ask on the website of the town hall or on site.
You can complete and submit your PC application file on the internet:
The CP form varies depending on whether the project involves a single-family home or another type of building:
You can complete your PC application using a form:
Application for a building permit for a detached house and/or its annexes (PCMI)
You can complete your PC application using a form:
Application for a building permit (other than for a detached house or its annexes)
You must submit your file to the Reception and User Service Office (Basu: titleContent) only by dematerialization:
Reception and user service office (Basu) in Paris: one-stop shop
Protected area
In a protected area, the type of city planning authorization depends on the floor area of your project:
Mezzanine or additional floor up to 20 m²
In a protected area, the creation of a mezzanine or an additional floor with a floor area of up to 20 m² is subject to DP.
Depending on whether your project is located in Paris or in another municipality, the application must be submitted:
- By dematerialized means according to the provisions taken by the commune (consult the website of the town hall or inquire on the spot)
- Per letter RAR: titleContent
- In person against receipt signed by the town hall.
General case
You must complete and submit your RFP file by dematerialized means according to the arrangements made by your municipality or on a paper form.
Ask on the website of the town hall or on site.
You can complete and submit your RFP application on the Internet:
You can complete your RFP application using a form:
Prior declaration of constructions and works not subject to building permits
In Paris
You must submit your file to the Reception and User Service Office (Basu: titleContent) only by dematerialization:
Reception and user service office (Basu) in Paris: one-stop shop
Mezzanine or additional floor of more than 20 m²
In a protected area, the creation of a mezzanine or an additional floor with a floor area greater than 20 m² is subject to PC.
Depending on the surface of your house before or after the work, the use of an architect may be required to deposit the PC.
Depending on whether your project is located in Paris or in another municipality, the application must be submitted:
- By dematerialized means according to the provisions taken by the commune (consult the website of the town hall or inquire on the spot)
- Per letter RAR: titleContent
- In person against receipt signed by the town hall.
General case
You must complete and submit your PC file by dematerialized means according to the arrangements made by your municipality or on a paper form.
Ask on the website of the town hall or on site.
You can complete and submit your PC application file on the internet:
The CP form varies depending on whether the project involves a single-family home or another type of building:
You can complete your PC application using a form:
Application for a building permit for a detached house and/or its annexes (PCMI)
You can complete your PC application using a form:
Application for a building permit (other than for a detached house or its annexes)
In Paris
You must submit your file to the Reception and User Service Office (Basu: titleContent) only by dematerialization:
Reception and user service office (Basu) in Paris: one-stop shop
FYI
The creation of a mezzanine or an additional floor subject to city planning authorization entails the payment of a development tax. You can make a amount simulation of your development tax.
The creation of the mezzanine or floor can also have an impact on your property taxes. For more information, you can contact your departmental property tax center.
Who shall I contact
Who can help me?
Find who can answer your questions in your region
For information on city planning regulation and administrative procedures
Administrative information by phone - Allô Service Public
For more information on this subject, you can contact Allô Service Public.
Attention: the service does not have access to users' personal files and therefore cannot provide information on their progress.
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The informants who answer you belong to the ministry in charge of housing and city planning.
For information on the local urban plan or your RFP or CP file
Town HallFor information on the local urban plan or on your DP or PC file in Paris
Paris: Reception and user service office (Basu)For information on property taxes
Departmental Center for Property Taxes (CDIF)
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