Following São Paulo's extraordinary growth during the 20th century, most of the old city buildings have given way to contemporary architecture. This means that most tourists sights are concentrated around the historical center, where 17th-century churches stand in the shadows of skyscrapers. The traditional ethnic neighborhoods are also fairly close to the center. Shopping and dining, though, are spread throughout the city. São Paulo can be divided in 7 main regions.

Centro Histórico:
The most cosmopolitan city in Brazil could have only a central area that is equally cosmopolitan. A universe of diverse people moves through the center of São Paulo; there are business people rushing to get to the stock market, groups of punks in search of the latest record and a number of university students hovering around the region attending night classes. Put on comfortable walking shoes and sunglasses, and discover hidden secrets that even many Paulistanos (as the inhabitants are called) may not know about.
Bixiga (Italian District)
Liberdade (Japanese District)
Sé and Vale do Anhangabaú
República
Bom Retiro and Luz

Expanded Center:
During the 20th century, little São Paulo became a giant metropolis and the historic downtown was just too small to hold its title. Since then, districts surrounding downtown in every direction became a circle known as Centro Expandido. The area is the most visited by tourists along with historic downtown, and home to the largest variety of services.
Paulista and Jardins
Itaim Bibi and Vila Olímpia
Vila Madalena and Pinheiros
Pacaembu and Higienópolis
Lapa, Pompéia and Barra Funda
Brás and Mooca
Vila Mariana and Ibirapuera

South Side:
On the South Zone you can go from residential green areas by a lake, middle-class villages with local commerce, to the area that has been called the new downtown, where the skyscraper lovers find themselves at home, together with high profile businessmen.
Brooklin.
Chácara Flora and Santo Amaro.
Interlagos.
Planalto Paulista and Vila Clementino
Saúde and Jabaquara.

West Side:
Home to the University of São Paulo, the State's Palace, and the largest soccer stadium in town, the West side offers a green suburban feeling in contrast with the chaotic megalopolis. The northwest neighborhoods of Rio Pequeno e Jaguaré hold lower class residential and industrial areas respectly.
Morumbi, Butantã and Vila Andrade
Rio Pequeno and Jaguaré

North Side:
In the northern area of São Paulo you can find neighborhoods with a small-town feel, such as Freguesia do Ó. Places of importance are Expo Center Norte, one of South America's biggest venues for fairs and exhibitions, Serra da Cantareira State Park and Anhembi Park. This region also hosts the Sambodromo and concentrates the bulk of samba schools of the city, as "Gaviões da Fiel", Unidos do Peruche, Rosas de Ouro and Imperio da Casa Verde.
Santana, Vila Guilherme and Cantareira

East Side:
The east side was the former industrial region of São Paulo and also the home to thousands of immigrants who settled in São Paulo during the early 20th century. It's the region with the largest population in the city, and also with the largest shopping mall (Aricanduva) and the largest urban park (Parque do Carmo). Some neighborhoods of interest are Vila Zelina, with its strong Lithuanian influence, and Mooca, the place that many italians chose as home. Tatuapé/Anália Franco is also worth noting for its "newly-rich" vibe.
Tatuapé, Penha and Anália Franco
Itaquera and Cidade Líder

Outskirts:
The places here are part of Greater Sao Paulo, although each is an independent municipality:
Paranapiacaba
Santo André