With this said there is only one way that interns can legally work and none of the intern placement companies are doing this legally. Only some companies are doing this legally. If you would like more information about this, please let me know.
My (Chinese) publishing house is trying to find out how to legally hire a (foreign) intern, but they have been unable to find any clear information about this. I've been trying to help them find out, but have come up short.
If you know the regulations about how to do this legally, please do share! I'd like to pass it along to my company's foreign affairs department.