Architecture
Notre Dame des Victoires
XVIIth century church,
The 2nd arrondissement covers some of the nicest old parts of Paris.
Place des Victoires
Beautiful round 'square' with an equestrian statue of King Louis the XIVth and matching XVIIth century buildings.
History
La Tour Jean-sans-Peur
One of the last remnants of medieval Paris outside of the 4th, this tower was once part of a castle called l'hôtel de Bourgogne
There have been dozens of attempts by various regimes at all levels including the city, the state and the church to chase the ladies of "love for a price" away from the eastern end of the second arrondissement, but for some reason they always come back. Interestingly, the word "bordello" originates here from the boards that the women used to subdivide the rooms they rented in houses along the rue Saint Denis and others.
The press has had nearly as long a run in the neighbourhood just to the west, and several of France's major newspapers still maintain offices here.
la Bibliothèque Nationale de France, Richelieu
Especially try to visit the cabinet des Médailles.