Hi, I'm not in a postion to specically answer your question concerning a mortgage as we released equity on an investment property in Ireland so were cash buyers in France (2007/2008). However, one important lesson we are now aware of is that as a purchaser (you pay the immoblier fees @ ~7%, so that could be an approximate agency fee that you have to pay of €10K.), there are more cost effective ways to purchase a property in France.
We since sold that property in France, but in all likelyhood, will purhcase again, we will not simply walk up to an agency niaively in order to purchase a property. Consider purchasing directly from a Notaire (not an Immoblier) where the fees will be approximately 50% of those charged by an Immoblier), or better yet, direct from a seller.
Finally, I cannot over-stress the importance of having all key surveys performed including seismic and earthquake (yes, really, especially in the south of France). Also Flood zone reports are very improtant if purchasing an individual plot.
Good luck with your purchase.