The duration of the validity of planning consents has been increased from two to three years, in order to give a boost to the flagging housing market.

If you are granted planning permission for a construction or renovation project in France, there is a two year maximum period allowed for the start of construction works.

If building works do not commence within this period, and then proceed in a regular manner, the authorisation is deemed to have expired.

The government have recently decreed that this period of delay be increased to three years.

In practice, this means that a planning consent may be valid for four years, for it is ordinarily possible to make an application to extend it for a further year, subject to complying with due procedure.

It is a change which applies to both planning consents (permis de construire) and for the lesser works declarations (déclaration préalable). It also applies to demolition permits, in the more limited circumstances where these are required.

The extension of the period of validity applies to all consents outstanding at 31st December 2014, and those that are approved up to 31st December 2015.

Thus, a planning consent granted in January 2013 will now be valid until January 2016, where previously it would have expired in January 2015 if works had not commenced and continued on site.

Such a prolongation of the consent is granted on request from the applicant, and is subject to no change in planning regulations having unfavourably affected the consent granted.

Arthur Cutler of planning consultancy French Plans states that: "The measure mirrors that taken in 2008, when the economic crisis obliged the government to grant an additional year of duration to planning consents then in place or granted up to 31st December 2010.Where a planning consent granted in 2010 has already benefited from an extension of time, the new measure grants this consent a further year."

Although an additional year has been granted, not only must the applicant start building works within three years (and make a declaration to that effect), but they must also proceed in a reasonably regular manner, failing which the planning authority would be entitled to withdraw the consent.

So even if works are started on site within the three-year period, but then ceased for a period of at least a year, planning permission can be deemed to have been rescinded.

As a general rule, the local planning authorities take a relaxed attitude to slow progress on site, but this may not always be the case where, for example, neighbours oppose the development, as they may decide to request that the planning permission be withdrawn, a demand that the planning authority would then be required to act on.