Here's a charming article about Sao Paulo's famous nightlife area that is also very pleasant during the day.
Arty, trendy and 'cool' Vila Madalena is a lovely place to hang out, forget time, visit small art galleries inbetween snacking or having a beer at the boutique restaurants spilling onto the pavement. Or sit and watch the world go by as you wait for inspiration for your next masterpiece. But be warned: at night and incredibly so at the weekends, traffic and the sheer volumes of young people make getting around quite slow. You need to book your restaurant in advance because, as you enjoy chatting quietly over a cool glass of choppe after the heat of the day, a vast army of chic bar-hoppers will be doing the same thing. Daytime is relaxed: and nighttime is intense!
It's one of the best places in Sao Paulo to enjoy the warmth and hospitality of the wonderful people who live here (and are rightly proud of their amazing city.)