Huatei has noted that a number of vessels recently had been punished by China’s MSA for failing to fly, improperly flying, or flying damaged or defiled examples of the National Flag of the People’s Republic of China.
Vessels need to fly the Chinese National Flag of the correct dimensions, according to the size of the vessel, at the appropriate time and place. It was suggested that the responsible crew members on board should be made familiar with the requirements and that ships check carefully whether they are equipped with standard Chinese National Flag prior to entering Chinese waters.
Precautions for Flying the Chinese National Flag
Ships Required to Fly the Chinese National Flag;
The following Chinese ships shall fly the Chinese National Flag daily:
（1）Ships of 50 gross tons and above.
（2）Ships sailing in waters outside China’s territorial waters and in Hong Kong or Macau.
（3）Official ships.
Foreign ships entering the internal waters, ports, and anchorages of the People’s Republic of China shall fly the Chinese National Flag daily
Where should Ships Fly the Chinese National Flag?
（1）Chinese ships shall fly the Chinese National Flag on the ensign staff. If there is no ensign staff fitted at the ship’s stern, it shall be displayed on the top of the bridge signal pole or on the starboard yard arm.
（2）Foreign ships shall fly the Chinese National Flag on the top of the foremast or on the top of the bridge signal pole or on the starboard yard arm.
（3）When the Chinese National Flag and other flags are simultaneously flown on the starboard yard arm of the bridge signal pole, the Chinese National Flag shall be displayed on the outermost side.
The size of the flag required depends upon the size of the ship.
https://www.piclub.or.jp/wp-content/uploads/2023/09/Huatai-Circular-Ref.-PNI-2023-8-1.pdf
https://north-standard.com/insights/news/china-enforces-flag-flying-requirements/