I have heard that there are more French Catholics attending the Traditional Latin Mass than the New (post-Vatican II) Mass. The SSPX is the largest traditionalist group in France, but there are others such as the FSSP (Fraternal Society of St. Peter). The SSPX has good relations with Pope Benedict but is at odds with many of the liberal French bishops.
I’m not an SSPXer nor an expert on their relationship with the Church at the moment, but I have to admit, when I saw this headline, my first thought was that it was SSPXers who did this.