France’s Olivier Duhamel, a prominent political scientist and TV host, has announced on Twitter that he would be stepping down from all further public engagements to “preserve the institutions in which I work” after being accused in a new book of incest with his stepson. His Twitter account has since been deleted. Author Camille Kouchner’s book, La Familia Grande, accuses Duhamel, who was also head of the Fondation Nationale des Sciences Politiques, of persistently abusing her twin brother from the time he was 14, which the brother confirmed to Le Monde, telling the newspaper, “I confirm that what my sister has written about the actions of Olivier Duhamel toward me is correct.” The twins are the children of Bernard Kouchner, co-founder of Doctors Without Borders, and Évelyne Pisier, the late writer who married Duhamel. Several outlets report they were not able to contact Duhamel for comment, but he did tell France’s weekly magazine L’Obs: “I do not react, and I have nothing to say. Anything I might say would, in any event, be, I don’t know, distorted.”