It's not one street, but a few, around the Centre Pompidou, also called Beaubourg, which are going to attract you. You'll find huge shops selling a variety of postcards and posters, and funny clothes boutiques. You're in the 4th area, but carry on and cross the Boulevard Sébastopol and you'll arrive in the 1st area, at the Forum des Halles (created in the 70's), an underground shopping center built on several levels, with all the chain shops you can imagine. But this place does't have a good reputation, because of freaky people hanging around (drug addicts meeting there for their deals)... Personnaly, I never had any problems and I enjoy shopping there! A project was born to rebuilt the whole center and to make it a nicer, and more secure and open place.