In Assassin's Creed Unity, Paris is the main setting for Arno Dorian's story.
Unity takes place during the French Revolution, beginning in 1789 and continuing through the upheaval that transformed France. Arno Dorian, raised in Versailles and later inducted into the Assassin Brotherhood, investigates a conspiracy while moving through revolutionary Paris, including districts, landmarks, and crowded streets designed for large-scale exploration.
Versailles appears in the game, especially during its opening section, but it is not the principal city setting. Paris is also the location of the game's cooperative missions, which allow multiple players to undertake Assassin contracts together. Historical figures and events are woven into the fictional conflict between Assassins and Templars, so the story should not be treated as a literal account of the Revolution.