Carol has brought up an interesting phenomena. Yes, the flagship stores of both Galeries Lafayette and Printemps on Boulevard Haussmann have an interesting set up on the ground floor, something that isn't in any of their other stores or the BHV. This was developed once tours from some newly-rich countries started coming to Paris and the participants had limited shopping time but wanted status goods to take home.
You'll find a small boutique of every luxury brand on these two ground floors, with accompanying detax offices, waiting rooms for bus tours that have a time slot to enter the area, etc. You'll see lines of people from these bus tours, waiting at the boutiques to buy luxury goods to take home to their countries. The spaces are designed for quick sales. Most of the customers know what they want before they get there.
Once you go upstairs, there is a larger choice of all kinds of goods, including some of the same luxury brands found on the ground floor.