[DTogo]

You nailed it! You can also tell by where the poured concrete wall meets the floor, and the way the flag curls at the ends. Definitely fake.

[Ex-Dem]

the way the flag curls at the ends.

You're absolutely right. It looks as if someone cut up a little square of black fabric and crudely painted it. A real flag of that size would be far too heavy to curl over in that way, which you mentioned.