On this website there are job offers of all working groups of the Insitute.
It can be offers for scientists, students, temporary contracts, internship or school jobs.
Take the time to have a look, even if permament jobs are quite rare, there are always research and development funded projects on a temporary basis.
Actual Job Offers from the Working Groups:
Or take a look at the job offers direct at the FU Berlin Job Advertisment Online.
Here is the Link for job offers at the Freien Universität Berlin