Background check authenticated for chinese work visa

Hi, I'm a US citizen and I was living in Germany the past two years but in november 2017 i moved to china. I got my background check and authenticated by Bonn office and I thought that was good enough for me to use it to apply for my work Z type but apparently I also need to get it authenticated by the chinese embassy in China...i'll have to send my background check back to Germany in order to send it to the chinese embassy in Germany but I'm not sure which embassy to send it to...is it to berlin? And also is there a special form i need to fill out when all I need is for it to be authenticated?? And is there a fee? Thanks!