A picture that summarise this comment
EDIT: oh that's the flag of the Chinese communist party: https://en.wikipedia.org/wiki/Chinese_Communist_Party
For some reason I expected that they would just use the Chinese flag itself, since there's no plurality.
The woman in red on our right also doesn't seem to be holding it. It's perhaps a cardboard sign or something? Maybe the picture of the flag was put over it?
Again, I'm no expert but it looks off to me.
[1] from https://www.jenniferzengblog.com/home/2020/8/5/bytedance-hea..., which also has archive links for the page in question and additional circumstantial evidence.
fotoforensics.com/analysis.php?id=ffaac5beff95e49e8bd59097ac36afb61e83086c.59039&show=ela