The information that can be found:
The sentence of writing couplets on the party flag was originally proposed on 2014-06-05.
"Writing Couplets on the Party Flag" and "Poetry Flying the Party Flag" Call for Contributions (Full Text Excerpt)
2014-06-05 17:05:46 Source:? Xinhua Net
Editor's Note: To commemorate the 93rd anniversary of the founding of the Communist Party of China, starting from May 26, 2014, the "Party Building" magazine of the Central Propaganda Department, the Domestic Liaison Department of the China Federation of Literary and Art Circles, and the China Couplet Society , the Chinese Poetry Society and other units, *** jointly launched the "Writing Couplets on the Party Flag" and "Poems Flying the Party Flag" solicitation activities, with the deadline for submissions before July 1.