For those looking for the official tourist information office, it is on Avenue San Martin, three blocks east of Plaza Independencia, in a wonderful antique building on Av. San Martin on the east side of the street (facing west), between the side streets of Garibaldi (changes to Peatonal Sarmiento on the west side of Av. SM) and Catamarca (changes to Espejo on the west side of Av. SM).  The east/west streets in the city center have three names:  one name on the west side of Belgrano, a second name between Belgrano and Av. San Martin, and a third name on the east side of Av. San Martin.  Sounds horrible, but it isn't if you have any kind of a map at all.