Flag of the Communist Party of Kampuchea, the ruling party of Democratic Kampuchea. This version of the flag is in a 2:3 ratio, to match the flag of Democratic Kampuchea. The original file can be found at File:Banner_of_the_Communist_Party_of_Kampuchea.svg. As it does not appear from photos that the flag was standardized, use whichever file is deemed more suitable in the circumstance.
Own work
Thespoondragon