Which supermarket uses light communication technology to revolutionize grocery shopping?

The Carrefour hypermarket replaced all its fluorescent lighting with 800 linear LED fixtures that can, via smartphone, lead shoppers directly to items on their grocery list. 

Using Philips' Visible Light Communication technology, each fixture transmits a unique code that can be picked up by a shopper's smartphone camera. The code is then read by Carrefour's mobile iOS app to guide shoppers to the appropriate aisle. 

The system also does more than help shoppers navigate a large store: Paired with a development kit, a cloud-based location database allows users to develop and customize their own applications.