How? According to Chanel's corporate website, they only sell through their own boutiques and authorized retail partners. This is known as a selective distribution agreement, and here is a 2008 report on internet sales models (prepared for Chanel) which articulates the differences from normal wholesale-retail models: http://www.crai.com/ecp/assets/Selective_distribution_Caffar...
My whole point is that no, you can't just go into business as a Chanel retailer, and you'll find the same is true for Hermes, LV, and a variety of other luxury brands. A great many high-value manufacturers make use of selective or exclusive distribution agreements to maintain price discrimination and market positioning for their brand across a global market.