I was there in May and visiting the Champs des Elysees store was right up there with seeing the Mona Lisa
Prepare for it to be crowded but definately go, as everyone else said, its pretty amazing. I also went by a few of the other boutiques in the city and they seemed much like those found in the US!
Have fun!
p.s. go upstairs to make your purchases, it's so much quieter and the SA's are more attentive. There's a lot of tourists just "browsing" downstairs . . .
, i already went. I shoulda put it in a seperate thread. . Pics and summary on page 2.