Historian, Professor Emeritus at the Sorbonne, member of the Academy of Moral and Political Sciences, and President of the Institute of Comparative Strategy. His research areas focus on international relations in the 20th century, particularly on World War I and East-West relations after 1945. His recent works include La Guerre froide de la France, 1941-1990 (The Cold War of France, 1941-1990) published by Tallandier in 2018, and La Grande Illusion. Quand la France perdait la paix, 1914-1920 (The Great Illusion: When France Lost the Peace, 1914-1920) published by Tallandier in 2015.