I can't find much biographical information about her on the Internet. But you might try this Financial Times article about early professional fashion photography models; scroll down to locate the part about Koopman. (For American English speakers, her Dutch last name would be pronounced something like COPE-man.)
In summary, she was part Dutch and part Javanese/Chinese, was pursued by rich, powerful men, imprisoned by the Germans during World War 2 and lived the rest of her life with a female art dealer. If this interests you, this biography will be published in September. And if you can read French, that version has been available for a while.
Here is what the fuss was about:
This image his credited on some Web sites as being of Koopman, but I'm not sure. For instance, the eyes and eyebrows seem wrong.