Rousseau was a French-Swiss guy who suggested getting rid of the class system decades before the French Revolution. And that makes him a strong influence on the Declaration of the Rights of Man and Citizen.

Rousseau had some ideas that were way ahead of his time. He suggested that there's a social contract between leaders and the people they govern. If the contract is violated, the people should replace their leaders—a bold idea in a time of monarchies. He also said that when society makes distinctions between people—like calling some of them nobles and others peasants—that's the root of all inequality and unhappiness in the world.

He took this idea to the extreme by suggesting people were better off living in the wilderness without the burdens of society. Most people choose not to go that far (um, modern plumbing is also a major source of human happiness).

Even without people running off to the woods, he probably would have really liked the Declaration of the Rights of Man and Citizen; it was finally putting his philosophy to use.