This takes me back to the Japan - Film case:
South Korean lawmakers are finalising legislation that would restrict the opening and operation of large urban supermarkets – a potential blow to Tesco, which counts the country as its biggest overseas market.
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Leftwing South Korean politicians began targeting Tesco early this year when it opened a “super-supermarket” in the port of Incheon, near Seoul. Tesco is suing protesters for about Won300m ($268,000) in damages to its business. The clash spurred opposition legislators to propose restrictions that recently gained support from the ruling conservative party.
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One bill that is moving through the South Korean parliament would require retail chains to seek special permission from local government before opening a super-supermarket, meaning a store of 1,000-3,000 sq metres, within 500 metres of a “traditional market” – a term that is very broadly defined in order to include the ubiquitous corner shop.
Another bill, opposed by some conservatives because they fear it runs counter to World Trade Organisation rules, would enable small shopkeepers to demand the temporary closure of a super-supermarket if they were able to prove it was eroding their business. Parliamentarians hope to vote on the bills by October 25.
Tesco – which operates more than 300 stores under the Homeplus brand in South Korea – argues that both bills would conflict with WTO rules and would also unfairly target super-supermarkets while placing no restrictions on convenience store chains.
I'm not sure exactly what violations of WTO rules they have in mind. Perhaps there is something in Korea's GATS Schedule, and they are thinking about market access or de facto discrimination.