Are you still looking for a gite - I have only just "tuned in" to the forum after a long absence.
Have you logged on to www.gites-de-france.com and searched via the Department you are interested in?
You don't say when you need it but even if it will be in the peak month of August there are so many gites that I would be surprised if you fail to find one.
We have sometimes left it til the day of arrival when we have been moving from place to place, admittedly not in August..
As well as gites there is the "clevances" site which is part of an official scheme for the classification of furnished properties.
Gites (and others) usually now provide a more comfortable standard than we found 35 years ago but we usually go for a minimum of 3 ears of corn and, even then, north American friends and relatives who have joined us on holiday have not always found the accommodation quite up to their scratch.
If all else falis I just Google "Self catering house wherever" then you get a vast choice, often with the option to book directly with the owner.
Best regards and Good Luck.