The question of whether or not a violent revolution is justified or not is a subjective one that is judged differently depending on where one finds oneself in reference to the political spectrum. Even contemporary progressive conservatives would undoubtedly dissuade the notion that violent revolutionary change is ever justified or needed, while others, such as those living in regimes that were set up through revolutions or violent upheavals, could not conceive of anything but violence for the establishment of what, at least they perceive as, a more just society. In addition to the political perspective, justifications for revolutions are also subject to cultural views. Most French citizens for instance (save of course for the Monarchists) see the French Revolution as the triumphant and necessary overthrow of tyranny while many British citizens, looking kindly upon their own constitutional monarchy, may be put off by the seemingly unnecessary brutality of the great terror. Similarly, in modern post-Soviet Russia there are still those who hold to the old revolutionary ideals that glorified the Bolsheviks as the saviors of the Russian people, while most Western democracies have seen the second 1917 revolution (the anti-democratic Bolshevik revolt against the Kerensky government) as an unnecessary bloodbath. Putting aside the subjective views of both cultural and political extremes, an inter-subjective standard of some kind of criteria may be said to exist. One may base such a standard's criteria on the very simple and all-encompassing notion of utilitarian progress under which any change that betters the situation of the majority is justified. Under such a standard both revolutions could conceivably be justified if it could be demonstrated that their outcome resulted in a situation more favourable to the majority.
Such an argument could easily be made for the 1789 French Revolution.