In the course of making a decision about which timber frame house to build, we visited a Huf house in the Charente which was just about complete. The quality of both materials and the build itself was exceptional - which is why they are so expensive 
We originally considered building a house using paille bales and discussed this with the mairie at the local town where we looked at some suitable land we were considering purchasing at the time. He was fascinated by the prospect and would not have stood in the way of the project - indeed, he would have encouraged it. Sadly the project came to nothing. Also not sure how the mairie would view it fitting in here because the permis on the land we were looking at had had expired and would unlikely be renewed as the local plan had changed in the meantime.
The French do not seem to have the same desire to see rows and rows of houses all looking the same throughout the countryside as seems to be the case elsewhere. The only exception seems to be where the property is in close proximity to national landmarks and churches.