When dictatorship is a fact, revolution becomes a right.

[Quand la dictature est un fait, la révolution devient un droit.]

Victor Hugo (1802–1885) French writer, journalist, human rights activist, politician

(Attributed)

While in keeping with his opposition to the regime of Napoleon III, I have been unable to find any primary source or citation in English or French for this quotation (that Time Magazine (1957-06-03) used the quote doesn't really count).