For the last 10 years, I believe that this is the first time it happened, due to the financial crisis we are passing thru.
Do you know in what area of the city is the apartment she is going to lease?
I´d recommend the "Jardins" area.
There is a great variety of restaurants in this location. Some very valuable ones and some very expensive. There are very good bars also.
But this neighbourhood offers one of the best living qualities of São Paulo. There she´ll be able to find anything she wants in a matter of minutes, by walking or by car.
If she wants to have a nice walk, along with many shops, restaurants and other nice places to hang around, I´d tell her to spend an afternoon at the "Oscar Freire Street".
This street is famous for being one of the most luxurious streets of the world with all the expensive brands stores that are located there. If she wants to have a good lunch, she could go to this street, eat at Tatou restaurant, and then, if she likes, have an excellent cake or pie at Cristallo or a good Haagen Dasz ice cream.
Here are some pics of this place (note that some construction were going on, but now they´re all complete):
There are lots of interesting places to visit here.
If she wants something more cultural, in Avenida Paulista there is MASP - São Paulo´s Museum of Art. It has some time I don´t go there, but it is great!! There´s also the Soccer Museum at the Pacaembu Stadium, which is brand new, if she is interested in sports, among others.
Well, I hope this post helps a little bit.