The problem is you can't just say the average in Gemany is figure A and that is below what I earn in Israel. The salary ranges can vary massively across whole countries so much so that the city you are applying in could be well above the average.
I'm in the UK for example and work in London and most jobs I get have a salary between £75k to £85k with contract rates at about £450 per day. In Manchester however I could only expect £30k to £45k for doing the same job.
According to develop the average UK game dev salary is £32k whilst the average software developer outside of games is £45k but, I already know that there is an almost limitless number of jobs paying double this amount in London.
Instead of looking what the average is in Germany you should look at what the average is at the actual company you are interviewing at. There must be reviews on sites like Glassdoor where previous staff have reviewed the company and detailed the salaries that they have earned.