Having sent off a Déclaration Préalable to the mairie about 6 weeks ago for some clients and not heard anything, I decided to contact Dinan planning office this morning. They confirmed to us in writing on 2nd February 2010 that they received all the necessary plans, photos and other information for our project. From that day, they had 4 weeks to get back to us. As they have not contacted us, the planning consent is automatically granted. It was reassuring to get a confirmation by phone though!
I can now contact the builder for him to start work as soon as possible.
You should never start any building or renovation jobs before you get the consent from the mairie otherwise you can get fined and even go to prison!
See my other post here about demolition permit.