I found this page on Karriere Manager Magazin that'll tell you if what you are being paid is adapted to your qualifications, by comparing it to what the salaries on the market are. You'll have to take a test in the form of a questionnaire. The results are the analysis made of your answers by a specialized institute (which name you'll find on the page). I am pretty sure this test is only valid for Germany. I didn't take the test. First of all I don't care at all at this stage of my career, Secondly I am not ready to pay the 10 euros :D
Hope it'll be of use to some of you.
Marwane El Kharbili.