Permis de construire

Hi everyone

We need to apply for permits de construire to renovate some derelict farm buildings. Is anyone able to confirm the rules regarding when you need an architect? Ie floor area/habitable space, whether it's external or internal measurements, whether it's both floors, whether ceiling height comes into play? Have received varying advice so am hoping to clarify before going to Mairie with plans.

Thank you.

Hi Sally,

I'm studying for my real estate license in France right now, so I can translate for you what the books say:

- You need a permis de construire for all new construction over 20 m2 floor surface (40 m2 in an urban zone with a PLU), or

- If you create an opening to the exterior, enlargen one, or modify the load-bearing structures of an existing structure while changing its "destination" or usage (ie. farm building to habitation).

- If the floor surface of the building(s) exceeds 170 m2 cumulative, then you must have an architect oversee the construction/renovation.

- You only need a déclaration préalable de travaux if: the work creates less than 20 m2 of floor space (40 m2 in urban zone) and does not bring the entire structure over 170 m2; you are just modifying the exterior (and not creating any openings); you are changing the "destination" or usage of the building (without modifying any load-bearing structures).

Hope this helps,


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Hello, I'm on several ex-pat forums (fora?) and am always surprised by this type of question.

Make an appointment with a local architect and ask him/her.

Thanks for your help. Greatly appreciated.

When trying to avoid architect costs the last thing you want to do is have an appointment with one!

What makes you think they will make a poteniel client pay for 20 minutes of advice?

I would have thought that the whole point of this forum would be to be able to ask people a general question of procedure rather than waste the time of an unpaid architect ? Why would you be on five forums if you question their mere function? Presumably to get five architects or artisans to make unpaid site visits in the hope of their securing some paid work?

Hello the troll

Thanks Michael. We are all sorted now and didn't need an architect or, as it happens, a permis de construire. I do find it extremely fustrating when people make unhelpful comments instead of sharing a tiny bit of their knowledge. We have found most people really willing to help us and hopefully I will do the same by writing about our experiences as "newbies" who have to find out all the relevant information for ourselves so that it can help other people in the same situation.

Thank you to everyone who tried to help us.

Hi Denelle,

We've just received our Permis de Construire approval. We used an architecte to draw up the PC document and then subsequently the "plans d'execution". However is it true that the law says one must have an architecte oversee the construction (over 170m2)? We were under the impression that it was just the plans that had to be done or approved by an architecte.

Appreciate any input!


OK here's a tiny bit of knowledge: as from July this year the surface area below which you don't need an architect was reduced from 170m2 to 150m2.

Might be useful to somebody.

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Ha ha never ask a plumber if you need to change your taps :-)

Thanks for that info, Anna. Did not know that it had been reduced before you need an architect.

OH done some checking and the law has been passed but the date which it is affected from, has not been decided. So if we understand correctly, the 170m2 still applies (not sure how long for)

Plse correct me if I'm wrong.


That's my understanding too. But if one is about to construct a house between 150 and 170m2 it would be best to confirm.

Our architect knows we are not going to use him for the suivi and has never said we need to have an architect for that, neither have the builders we have already consulted. Other architects quoted for both drawings separately and for drawings + suivi.

I’ve just picked up one of those free property mags and the first two pages were all about various building permits and it would seem that the 170 rule is still in force.

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My feeling is that it is useful to talk to your mairie before you make the application. Two weeks ago a mason told me I needed a declaration prealable for repointing. The mairie told me I didn’t, they just wanted the repointing to be sympathetic in colour and style. I asked about new window openings in the back of the house and was told I only needed a declaration prealable… The mason also told me that the mairie can overrule the Architectes du Batiments de France. However I do live in a village where many old houses have been disfigured with cement renderings and upvc windows and shutters, so I imagine my local mairie prioritises development over aesthetics.


Great advice Vivien.

I am having a roofed terrace of about 30sqm built, open on 3 sides, not attached to the house, using an existing garden wall as a wind break. Can any of those in the know tell me if any sort of permission is required? Thanks in advance.

Thanks, though given the atrocities allowed by mairies I think I’d like to
see more regulation…