In Assassin's Creed Unity, Paris is the main setting.
The 2014 game takes place during the French Revolution, beginning in 1789 and covering major events in the revolutionary period. Players explore a detailed version of Paris, including landmarks, districts, crowds, and interiors designed around the city's changing political climate.
The protagonist is Arno Dorian, a French Assassin who becomes involved in the Brotherhood while investigating the death of his adoptive father. His story also connects him to Élise de la Serre, a Templar and his childhood friend.
Paris is not the setting of Assassin's Creed Syndicate, which follows the Frye twins in Victorian London. Rome is especially associated with Assassin's Creed: Brotherhood, while Madrid is not the principal city of Unity.