Kant was supportive of the idea of a French Revolution before 1789, the year when the real French Revolution began. He was convinced that the revolution would lead to the rise of a culture of liberty, science, reason, and religious ethics in Europe. But he never publicly voiced his support for the French Revolution and he was shocked when he learned of the massive violence that the revolutionaries were unleashing in France. To his close associates, he used to say with agitation that the revolutionaries were children with weapons who had gone out of control.
In her book Lectures on Kant's Political Philosophy, Hannah Arendt writes:
“[Kant’s] final position on the French Revolution, an event that played a central role in his old age, when he waited with great impatience every day for the newspapers, was decided by this attitude of the mere spectator, of those "who are not engaged in the game themselves" but only follow it with "wishful, passionate participation," which certainly did not mean, least of all for Kant, that they now wanted to make a revolution; their sympathy arose from mere "contemplative pleasure and inactive delight.”