The Enlightenment had a profound impact on the French Revolution by promoting ideas of liberty, equality, and fraternity. Thinkers such as Rousseau, Voltaire, and Montesquieu emphasized reason, individual rights, and the critique of absolute monarchy. These philosophical concepts challenged the traditional hierarchies of French society and inspired the revolutionaries to seek political and social reform. The Enlightenment encouraged the belief that the people held the power to overthrow oppressive regimes, leading to the demand for democracy and the establishment of the Declaration of the Rights of Man and of the Citizen in 1789.