If you are a Blue Card Holder and you have worked in Germany for 21 months, you can apply for permanent residency if you have a B1 level in the German Language. In my case, I have taken the courses but didn't get the certificates. I contacted them and they told me if you don't have the certificate, you need to prove that you have the B1 level in German during the interview. That's what I would like to know. What kind of questions do they ask during that interview?
This won't work. If you don't have the certificates, they expect you being much more fluent in German than the certificates would prove. This is mainly a shortcut for people whose mother language is German but who haven't got the citizenship for odd reasons. They don't need stupid papers to prove their skills. Expect the whole interview being in German and you have to understand almost all of it. They may ask you anything
EDIT: This was my answer before the question was edited.
You mean the Sicherheitsrechtliche Befragung? That's a form which you have to fill out, not an interview. If you don't speak German, you can do it at the Ausländerbehörde, with the help of an interpreter.
They ask you about your political activities, if you collected money for political organisations in other countries, if you advocated violent activities in other countries, if you had been part of irregular troops, etc. Also, if you simply had been in some countries such as Usbekistan, but also Bosnia and Albania or if you ever used faked licenses.
Should you have been involved in such activities, not necessarily illegal ones or ones being a common, unpunished "crime" in your home country (such as driving with a fake license), I strongly recommend to contact a specialized lawyer.
(Yes, Bavaria deported people because they said they never did something illegal, and were found to have used a fake driving license in their home country.)