Hiring a castle in France is not the same as renting a castle in Scotland or renting a castle in Italy. The difference is not just geographic. Although, together with Castillo in Spain, words are commonly used as translations for one another and extracted from the same Latin root, they refer entirely to different types of properties.
Considering that the English castle is a very specific type of building, originally a fortified residence for a feudal ruler, usually of large size and immediately recognizable by its (usually) slender towers, the French castle is not just a castle in France. Although the French castle is a literal translation for the English castle, the term is actually applied much more widely, and can in fact mean any old or large country house. In French, the specific term castle fort is used for a medieval, fortified castle. What distinguishes the French castle is that it is a magnificent residence in the countryside, unlike a city, the word "pale" standing for its city equivalent. Again, this is different from the English language, as the palace in England, Scotland, Wales or Ireland is just as likely to be found in the province.
As for someone looking for holiday rental, the significant difference is less likely to be social, historical or architectural, interesting, though these aspects are but one of the cost. A high-rise castle rental in England, Scotland, Wales or Ireland is reasonable to cost over twenty thousand pounds per week for exclusive use while you can rent a castle in France for only 3,000 euros a week, though it's probably what will be called in England a country house or even a country house. Since the medieval fortresses were originally the stronghold of the local ruler, their size would reflect its strength and the degree of its power, from small buildings that range from farms to fortified farms to large fortress bastions that dominate the country for miles around. Just as these masters even spread all over the British Isles and France, and the seats and symbols of their power. Yet many of these truly medieval buildings survive, and the vast majority of castles, castles, and houses for rent from the 17th and 18th centuries, and sometimes later.
As regards the whereabouts of the later castles and country houses, there was a substantial difference between France, on the one hand, and England, Scotland, Wales and Ireland. In the second largest houses of the aristocracy (which are sometimes referred to as castles, though not already serving for military purposes), were still scattered even around the ground, as they represent their owners, the local superiority, although their dominance was now more public than political, so Scotland rents can be hired in almost all countries.
In France, however, local social superiority was simply not worth it – all meaningful ambitions were focused on the king and court in Versailles, both for the aristocracy and for the new rich bourgeoisie that followed them. As such, rentals in France are more likely to be found in the center than in the periphery, in the Loire Valley, Normandy, Burgundy and Dordonne.
In Italy, the situation is different again. As in the UK, a castello (castle) is a medieval or Renaissance military fortress. The equivalent of renting a villa here is renting a villa. The urban equivalent of a rural house (like France in this respect) is the palace, although this term also includes the fortified residences of the merchant princes of the Renaissance Italian city states. Unlike France, however, it is possible to find villas in Italy almost everywhere on the peninsula – it is not as much a question as in England of the burden of local interests that are envisaged in the face of the gravity of the central government, but rather had no central authority, since Italy until the middle of the nineteenth century was a set of dozen or more independent states. As a result, you can find a castel or an Italian villa for rent from all over Sicily to Tuscany to Veneto.