If you are staying in the Moema/Ibiripuera area of Sao Paulo I highly recommend Villa Alvear (Rua Canario #408). At a meal there last week our main course pastas were good, but the real standouts were the appetizers -- spicy grilled chorizo, empanadas and mollejas, aka chicken gizzards. I did not know what mollejas were, so we asked the waiter. He motioned to his throad and said "glandulas", at which point I did a most un-chowhound thing and made a face. He said they were fabulous and that if we didn't like them he'd take them off the bill. And they were indeed delicious, lightly fried with a little squeeze of limon. I figured out the next day that they were chicken gizzards. Also, they have a terrific wine list and you can dress casually. Zero English on the menu, or heard from staff or other patrons.
No matter where you are staying in Sao Paulo, definitely go to Jun Sakamoto (Rua Lisboa #55, Pinheiros). It is tiny, no more that 40 seats and very popular, so definitely reserve ahead. We did an omakase/tasting menu that went like this: tuna tartare with foie gras gelee, simple sushi course, duck confit spring rolls, more complicated sushi course, whole steamed fish. Everything was wonderful. Excellent wine list with good prices (for Brazil) and a wide range of choices for white wine, which I have not often seen in South America. Two glasses of sake, 1 bottle of wine, 2 dinners, dessert and coffee was about $R500 -- or US$200, which is a bargain given the quality....but bring cash or Mastercard as they do not accept other cards (who knows why?).