You make a bad impression asking for a low salary and more importantly quite often you actually don't need to. In Germany there are quite often going rates for salary, even with hi-tech companies.
What happened to me personally a number of times was this:
- What are your salary expectations / requirements / wishes?
- Something to the tune of X.
- Ok, our company rate guideline says we can offer you Y.
Where X and Y would differ by up to 30% either way and even this big difference didn't mean my application was rejected. I can only guess that going right off the scale wouldn't come across very well.
Important tip: calculate how much to ask for
What is advertised with the job and how much you ask for is more than you'll effectively get. For me, a foreigner, the German income tax system was quite opaque and unpredictable. So I suggest you try reasoning up your required paycheck number (depends very much on where are you going to live, whether you need to support a family, if you maintain a car or two, how often you travel home on a train which can get quite expensive, etc.) and then look at for example this income deduction calculator and get the idea about what number to ask for (since the salary offers are usually pre-deduction and there for sure will be considerable deductions). The system gives advantage to the lowest income groups, but if you try out higher values (for example the average or median income), you'll quickly learn that at average levels and above the tax curve is quite steep and that getting a bit for you means asking for two to three bits from the employer, which puts your reasoning to quite a different perspective.