Hey,
i came back from a one week Paris trip just recently.
I once was in Paris for just one day and i did not like it, but now i love the city.
However, be aware of the astronomic prices. My friend and i visited 2 friends, which were studying in paris for 6 months we also lived in in st. germain, near the metro station st. germain de pres.
For the metro you should buy a weekend ticket on saturday and sunday, which is 3,40€ and for the others days perhaps the 10 ticktes mentioned by vics.
Paris is a tourist city and so you have to take care of your stuff, do always have an eye on you camera and you wallet, especially in very crowded places like champs elysees or the metro!
Paris has got some nice museums, the louvre of course, but it can be tiring to see that much paintings of the same bilbic scenes
🙂. So think about visiting the musee d'orsay for more modern art.
As you are living in st. germain i can heartly recommend the restaurant "au pied de fouet" in the "rue saint benoit 3"
http://www.aupieddefouet.com/English/Home, great prices and great food, you will have to wait for a free table, but a free róse will make the waiting easier.
I can also recommend to visit marais, it is a jewish quarter with a nice architecture and falaffel restaurants
🙂
What else can i say? enjoy the city, it's wonderful. Have a great time.