While the New York Times says Memoirs of a Geisha is still "awaiting approval" by China's censors and that "[g]overnment officials have denied considering a ban," at least one site -- Ireland On-line, of all places -- is reporting that a ban has indeed been put in place:
New movie Memoirs of a Geisha has been banned in China amid fears it will encourage widespread anti-Japanese ideologies.The casting of Chinese actresses Zhang Ziyi and Gong Li in the Japanese drama has already caused outrage in China -- because many regard geishas as prostitutes.
Bravo, Chinese censors! We don't know what we would do if anti-Japanese ideologies ever became widespread here in China. That would just be awful.
Also on Shanghaiist:
I geisha you’ll have to watch that crappy pirated DVD version
Zhang Ziyi has sex with Japanese men!
Extra! Extra! Pet pythons, Geisha-gate and another village melee

Gan Lulu spotted at the Shanghai Kitchen Expo!