Paris is well equipped in public transports. With one single metro ticket you can go anywhere within Paris city limits. That goes for Metro and RER. According to the length of your stay you better buy a pass called "Navigo" valid for a week or a month which gives you access to different concentrical sections from.
How to get there
Charles de Gaulle, George V, Franklin Roosevelt, Champs Elysees Clemenceau
RER A :
Charles de Gaulle Etoile
from the 2014-04-25 until the 2014-08-24
This spring one of the major parisian exhibits will be dedicated to Lucio Fontana. Fontana is thought to be one of the most influential visionaries of the last century. The MAM seeks to change that with its display on 200 of Fontana's works, including paintings, scupltures and installations.
Musée d’Art Moderne de la Ville de Paris