(a long word that essentially translates to "rental debt clearance certificate" - a document from your previous landlord which states that your rental history is in good standing)
If you can demonstrate good rental history, this can really help with the rental process. This document, given by your previous landlord, certifies that you always paid rent on time and have no debts. It shows to your potential new landlord that you are a reliable tenant.
If you have not yet paid rent before or are new to Germany, it can make the rental process more difficult. When you're asked to submit a rental debt clearance certificate, you can inform the landlord that you've never rented. Since this could be a disadvantage for you, it is advisable to enclose a parents' rent guarantee (see the Rental Guarantee Statement).
The General Credit Protection Association (abbreviated to SCHUFA in German) is the largest source of information on the creditworthiness of private individuals in Germany. A forecast is made about your future payment behavior based on your previous payment history.
In Berlin, where the demand for apartments is very high and the supply is terribly low, the SCHUFA credit rating is an indispensable document. To increase your chances of getting a flat, you should always bring your SCHUFA with you to viewings! Here you can request your own SCHUFA form.
Proof of income
The landlord requires a proof of income to make sure that you can afford the flat. The law states you can do this with your last 3 payslips. If you have worked for less than 3 months, you should submit a salary certificate certified by your employer and attach a copy of your employment contract. If you are self-employed, you can prove your earnings with your last tax statement.
If you are a student or otherwise without income, you should get a parental guarantee, confirming that they will guarantee the rent payment. Another option would be for your parents to sign the lease on your behalf. In these cases, they would need to prove their income.
Personal Information Sheet
When you visit a flat, you may be asked to fill out a questionnaire about your personal, family and economic situation. You should always answer truthfully, as the landlord is entitled to terminate a rental agreement in case of false claims. Questions about family planning, religion, sexual orientation, or membership in a political party are not allowed and do not have to be answered!
Permit for Subsidized Housing (WBS)
Some housing requires a permit for subsidized housing (abbreviated to WBS in German) in order to rent there. This requirement is usually noted in the housing description for a particular home. Issuing a WBS is income-based and anyone can apply for it if needed for themselves and their partner or family. The forms that are necessary for the WBS application can be filled out and handed in at all Berlin citizen's offices (Bürgeramt).
You can find out if you are eligible for a WBS residence permit here.
An important requirement for claiming a WBS is that you do not exceed the allowable income limit. If your total annual income (after deduction of all costs) does not exceed the income limit of 16,800 euros (as of 2017), you are most likely entitled to a residence permit.