Hi,
I am a postdoc and within a scholarship I had the opportunity to visit the university within a research grant provided by the DAAD. At the same time I am receiving my TVL salary from Uni-Oldenburg. Apparently the scholarshipis tax exempt. So far I haven't been required to submit my tax declaration. If I consider the fellowship that would lead to a different sum of tax. 
My questions are: 
1. Is the scholarship taxable when I am receiving a salary next to it as well? 
2  If yes do I need to submit my tax declaration?
Regards,
Rob