On November 11, 1918, in the morning, Georges Clemenceau declared to his chief of staff: 'We have won the war, we must now win the peace, and it will be even harder.' Indeed, in addition to German ill will, it will not only be necessary to reckon with the balanced diplomacy of the British who do not want to weaken Germany too much for the benefit of France, but also with the ambitions of American President Wilson, whose main principles democratic policies deprive Europeans of any annexation policy. Far from being appeasement, these unrecognized years were marked by turmoil and uncertainty. The war continued in the East, in the Baltic countries in 1919, between Poland and Russia from 1920 to 1921, between the Turks and the Greeks from 1919 to 1922, while the civil war in Russia caused the death of 5 to 7 million people. Above all, the specter of the victorious revolution in Russia creeps in from Germany to Hungary via Italy. The enemy is no longer quite Germanism, but Bolshevism, infiltrated in the form of the new communist parties of Europe. A radically new world was born, a new ideological era wedged between Wilson and Lenin, two messianisms alongside which France and Great Britain no longer play the leading role. While the illusion of lasting peace prevails, instabilities, bitterness and disappointments are already stoking the fire of revenge. Jean-Yves Le Naour delivers a brilliant and renewed - sometimes iconoclastic - study of this tragic end of the war, studying in particular the Treaty of Versailles, whose big loser was perhaps not Germany, but France.