A federation of all the french owners associations in direct contact and discussion with the government was created last year :
The web site is in french but they can answer in english to any question. They success in modifiying some parts of the law.
The first step being always to create an association or to get in close contact with french co owners. SOme Irish have done this with good results.
http://avocats.fr/space/paul.duvaux/content/leaseback-invest ments-in-french-residences---welcome-to-the-banana-republic_
1C724902-9FE6-4B71-88C9-352D97065268
Use and disseminate this
other website from a french lawyer (a page in english is provided and explain
very clearly what you have to do according to your situation).
Try to post a research on the following french forum (sub topic : looking for co owners):
http://www.cbanque.com/forum/forumdisplay.php?30-Recherche-p roprietaire