An unprecedented split is shaking up French publishing. ADVERTISEMENT ADVERTISEMENT On Wednesday, 115 writers published by Grasset announced that they were leaving the publishing house after Vincent Bolloré ousted its chairman Olivier Nora. In a joint letter, the authors denounced the "ideological war" waged by the ultraconservative billionaire - who owns the Hachette Livre Group, which includes Grasset - to "impose authoritarianism throughout culture and the media", and warned: "We will not