Chinese retaliation

China said it will tighten control on the activities of Christie's
International, hours after the auction house sold a pair of Qing Dynasty bronzes in Paris for 31.4 million euros ($40 million), ignoring calls to return them. London-based Christie's must give details of the ownership and provenance of any artifacts it wants to bring into or out of China, the State Administration of
Cultural Heritage said today in a statement on its Website. Antiques that are without papers won't be allowed to enter or leave. [Bloomberg]

To judge from the forums it would seem that many dealers and collectors agree with James Sung, a political science professor at City University in Hong Kong who said: "China has overreacted". I would like to ask Christie's international to what extent they would have been wanting to take into and bring out of China artefacts without the proper paperwork anyway? Surely the right answer to that question is "none". I find it very odd that collectors can question a foreign state's right to determine what it will and will not allow across its own borders.