The laws on French property ownership depend to a large degree on what type of property you buy. Farms and vineyards, for instance, are subject to different procedures and costs from non-commercial dwellings.
However, one issue that the British are unfamiliar with is that if your house is on more than one hectare of land, there might be intervention by The Société d’Amenagément Foncier et d’Establissement Rural (SAFER).
The job of this agency is to decide whether agricultural land should remain in agricultural use. In practice, it rarely exercises this right, but the notaire (a French lawyer who will hand the conveyancing of the property sale) is under an obligation to notify SAFER to give it the opportunity to object to any sale of substantial agricultural property.
SAFER has up to two months following completion of the contract to announce if it wishes to exercise its right. It it does so, then any agreement is null and void.
Make sure, when you’re buying, that objection by SAFER is one of the ‘clauses suspensives’ inserted in the compromis de vente (preliminary contract). That way, if SAFER should for some reason exercise its right of purchase, your deposit will be returned without delay.