- Feb 2019
During the 100 days - The coalition declared war against Napoleon and not France. He was branded an outlaw as part of the Congress of Vienna. Basically Napoleon was declared a war criminal.
At that point he was. He was simply too dangerous to them and they wanted to see him gone. They had a good reason, they fought 12 years of war against him and after all the destruction the wars caused they didn't want to see it happen again. Since he also returned from exile and took over France in the way he did it was clear that he wasn't done. His return also broke the Congress so it makes sense that they would attack him.