How much effect it ultimately will have I'm not in a position to say, but it's a heap of bad press for the Sarkozy camp, who has to play defense. The more dents in his armor the better, I say. Now, if this dust-up pushes the debate towards Sarkozy's rather unhealthy relationship with the media, even better, but I don't expect the media to be criticizing themselves.
"Stalinist tactics" sounds like a quasi-Godwin moment to me, but it might be par for the course.

"The basis of optimism is sheer terror" - Oscar Wilde