Sao Paulo is like Rio -on steroids! You have to exercise a high level of personal security - don't wear flashy jewellery (or any jewellery - with jewels - really, stick to the cheap stuff). Forget the fancy watch, keep the cell phone out of sight, lock the laptop in the boot of the car or back at the hotel, try not to look "lost", be careful going out at night and be very careful which taxi you use.
Download our Rio guide - the safety rules that apply there also apply in Sao Paulo.
This is NOT saying Sao paulo is not a good place to visit - it's an exciting and vibrant city with much to offer. Just use caution.
Get that Rio guide here:
http://www.worldnomads.com/guides/rio-insiders-guide about 2 years ago