In the middle of 1946 he was sent to China, and was appointed consul of Hankou. Mizzan arrived in China at 41, and went on to become the first secretary of the Italian Embassy in Nanjing. In China Mizzan lived firsthand the advent of Communism. Mizzan was the "highest Italian functionary in China among those who, among thousands difficulties, resisted and held their place after the outbreak of the war in Korea, albeit without recognition from Beijing." Mizzan found himself in the lead of the diplomatic relations between Italy and China after the Italian ambassador fled to Italy in 1950. He and the other functionaries weren't recognized and weren't given privileged status by the Chinese authorities, who considered them simply foreign citizens. Neither the functionaries nor their belongings nor the embassy buildings were given the privileged status normally acknowledged to diplomats. After the outbreak of the war in Korea, tension arose. The position of Mizzan and the other diplomats became uncomfortable, and the Italian state, after Mizzan's advice and the following consultation of former Italian ambassadors and scholars, decided to proceed with the burning of the archives containing political correspondence in Shanghai. As reported in a telegram sent by Mizzan to Rome in October 1950, the absence of immunity might've put him and his colleagues in an uncomfortable position, should they be caught unawares. The archives included correspondence from 1929 to 1943, and older one, and constituted "a cumbersome reminder of the past."