Macron is conviently distorting history. After the war, Europeans knew that nationalism could be a way of protecting peoples from aggression and acted accordingly to radically redefine the basis for many nations. Before World War I there were large scale empires. The Austro-Hungarian empire especially incompassed many peoples (ethnic Germans, Hungarians, Romanians, Czechs, Slovaks, Slovenes, Serbs, Croats, etc.). The tension of such an amalgam of peoples in one country initially sparked the war in the first place (a Serb assassinating the Austrian heir to the throne).
Europeans learned a lesson from that and began dividing people up by their ethnic/cultural/linguistic groups into separate nations to create less conflict. The Austro-Hungarian Empire was divided into Austria, Hungary, Czechoslavakia, and Yugoslavia. The Ottoman Empire (another Central Power) was likewise divided into even more separate countries and mandates. A lot of territory was shifted, such as East Prussia being given from German to Poland—not just as punishment but because the majority of people living in East Prussia were ethnic Poles. Other countries were also created based on local people’s wanting their own nation states to government themselves (Finland and the Baltic nations).
World War I led to a powerful drive for nationalism, but with the exception of Germany it was not done with the “spirit of revenge” but with the spirit of peace, safety, and the right of self-determination.
Today in Poland they are celebrating the 100 Year anniversary of Polish Independence.