A few weeks ago they posted a map showing average prices across various regions, you can download the pdf here.
It doesn't really tell you what your money will buy but it does give a decent comparison of relative values between say St Malo & Poitiers.
Once you have decided which region suits your requirements and budget then you can narrow your search by looking here.The Immoprix site gives a more detailed breakdown by department and areas within a department.
Found your ideal area - then why not take a look at some listings on FrenchEntree or Se Loger so that you get a rough idea of what your money will actually buy.
Once you have done this and have your financing in place then it's the ideal time to appoint a buying agent to help source the specific property and buy it at the lowest possible price for you.
Here’s us Brittany Gems and fourteen others we’d recommend....there's bound to be one near you!