According to Mediametrie (French audience rating agency), 27.6% of French web users visit blogs at least once a month. . 4 millions wrote comments and 3 millions created their own blog.
Most popular blog platforms are Skyblogs (from radio station Skyrock) with 4.17 millions visitors, followed by MSN Spaces (2.95 millions visitors), OverBlog (2.32 millions), Six Apart (1.87), Blogger (1.56) and BlogSpirit (1.3).
Article in French at ZDNet.fr
Mediametrie report in PDF here (en francais)