This is Ruth Lee, a hostess at a Chinese restaurant. On December 15th, 1941, on her day off, she went to the beach in Miami to sunbathe as usual. This time, however, she brought with her a Chinese flag so that she would not be mistaken for being Japanese.
Just a week before, on December 7, 1941, "a date which will live in infamy," Japanese planes had attacked U.S. naval bases at Pearl Harbor, killing more than 2,300 Americans.
Two months later, on February 19th, 1942, FDR gave the order to round up nearly 120,000 people of Japanese ancestry and force them into internment camps. Approximately 80,000 of them were born in America and were American citizens.
The flag shown in the photo is the flag of Nationalist China, which went into self-imposed exile to Taiwan after the Communist revolution. Today it is the official flag of Taiwan.