This article is taken from www.frenchentree.com a superb site on living and working in France
Obtaining permission to carry out renovation work is a complex subject. It's therefore essential that before starting (or even planning) any renovation work, you check the procedures that apply in your commune.

In all cases, you should go first to your local town hall and ask for the service d'urbanisme. In a large or medium-size town, this may be a separate department manned by an architect who's familiar with the buildings in the town. In a small town or village, the mayor himself and his assistant may deal with everything and will act as your liaison with the Direction Départementale de l'Equipment (DDE), which is responsible for approving all planning applications.

Failure to apply for planning permission can result in the demolition of renovation work and even of the whole building (within a short time) and the payment of a penalty, followed by endless, costly and often agonising negotiations with French administration.

Planning applications, however, aren't something to be afraid of. In most cases, reasonable requests for permission are sympathetically received and, unless your plans are outrageous or your property is listed, are unlikely to be rejected, although certain modifications may be required. In fact, any modifications are likely to be in your interest, and you're likely to receive helpful advice as to the best way to carry out your renovation, which will save you both money and time, as well as ensuring that the result is in keeping with local style and tradition.

Preparing a planning application can also be beneficial in helping you with your own planning.

Rules and regulations
Although there's general legislation governing planning applications that applies throughout France, detailed rules and regulations vary considerably from region to region, department to department, commune to commune and even village to village, which makes it impossible to list them all here. For example, in Côtes d'Armor in Brittany, you cannot usually obtain a permit to build a house less than 100m from a farmer's field. This may not apply in the heart of France.

Those planning to buy property for renovation in Brittany should note that planning regulations have been considerably tightened in recent years. Many small towns and villages have joined the Commune du Patrimoine Rural de Bretagne, which aims to maintain properties to their original specification, eg: only traditional fittings may be used and even the terrain may not be altered by tree planting without permission.

For this reason, it's essential to seek advice from people who know your area and can provide information specific to local regulations. Your first port of call, as in most matters to do with renovation, should be your local town hall. Nevertheless, certain rules apply in most areas, including the following:

* Rainwater from your roof must not run onto a neighbouring property.

* You may not construct a building or plant trees or shrubs within 2m of a neighbouring property.

* If a neighbouring wall is over 6m high, any building or plant must not exceed half the height of the wall.

Don't rely on estate agents, builders or other individuals to give you the correct information; you will be liable for any mistakes, not them.

There are essentially three types of permit (described below), and the first thing you must ascertain is which of these you will need (if any) and whether you can submit the application yourself or must employ an architect to do so on your behalf.

Using an architect
For any project to renovate (or construct) a building over 170m2 you will need a professional architect to draw up plans and make the planning application on your behalf. (You may of course use the services of an architect even if the area of the building is less than 170m2).

Calculating the relevant area, known as the 'surface hors d'oeuvre nette' (SHON), is more complicated than it might seem. All habitable areas must be included (eg: the first floor or roof if you're planning to turn this into bedrooms, as well as the ground floor) and measurements must include the thickness of the walls, which must therefore be measured to the outside face. However, the calculation normally excludes garages, basements, open areas at ground level (eg: a porch or terrace), balconies and any habitable area where the headroom is less than 1.8m, eg: in rooms under the eaves.

The cost of using an architect varies according to the size and complexity of the project, but normally starts at around E1,750.

Permis de démolir
A 'demolition permit' (un permis de démolir) may be required when you wish to demolish a building on your land, and you should check at the town hall before knocking anything down, irrespective of how dilapidated it is. A permit may also be required to lop or cut down trees or to clear ground for building (une demande d'autorisation de coupe ou d'abbatage d'arbres or une autorisation de défrichement).

Permis de construire
A building permit (un permis de construire) is required for any change to a property that affects its taxable value (valeur cadastrale), which normally includes the following:

* Any extension to a building, including a balcony or car port, of more than 20m2

* Changing the use of a building, eg: by converting a shed to a workshop

* Creation of additional accommodation, eg: by converting a loft or outbuilding

* Removing internal walls

* Construction of any outbuilding (eg: stables, kennels or garage) exceeding 20m2

* Enlarging existing doorways or windows or changing their style or inserting new windows (including most types of double-glazing)

* Changing the type of roof tile

* Erecting fences or walls or replacing a fence or wall with a different type of structure

* Installing a septic tank

* Digging a well

* Installing a swimming pool of over 20m2

* Installing a pond of over 50m2

* Installing a mobile home in the garden.

Planning permission may also be required for the following:

* Changing the colour of external walls, windows or shutters

* Removing rendering to expose external stone work or covering stone work with rendering

* Creating a roof terrace

* Creating a terrace or patio over 60cm high or covering more than 20m2

* Replacing front doors

* Installing security grilles

* Installing solar panels if they affect the external appearance of a building (ie: are mounted on the roof) - you may not need permission for panels at ground level

* Installing a satellite dish (une antenne parabole) more than 1m in diameter

* Removing trees (see Permis De Démolir above).

Déclaration de travaux
A 'declaration of work exempt from a building permit' ('une déclaration de travaux exemptés de permis de constuire', often referred to simply as une déclaration de travaux) is a kind of simplified building permit, which may be all that's required for work that doesn't change the use of a building or create new living space, or for minor alterations to a building, including the following:

* The installation of dormer windows or skylights where there's no existing roof aperture (provided these don't overlook a neighbouring property)

* An extension of less than 20m2, e.g. a garage, car port, kitchen or conservatory

* Constructing an outbuilding (e.g. garage or workshop) of less than 20m2

* Replacing roof tiles or other features with identical or similar items or materials (du travail à l'identique)

* Raising the height or otherwise altering the line or pitch of a roof

* Adding or replacing external doors or windows

* Building a swimming pool of less than 20m2.

* Adding internal walls

* A structure of less than 2m2 and less than 1.5m high

* A wall less than 2m high

* A patio less than 0.6m high

* Greenhouses up to 2,000m2, if less than 4m high

* Temporary structures on a building site

* Statues, monuments and works of art less occupying less than 40m3 and less than 12m high.

Taken from Renovating and Maintaining Your French Home by Joe Laredo. Survival Books. This book is available from the French Entrée bookshop.