Do I need to provide a police clearance certificate for my application?

Only if the position explicitly requires it. A police clearance certificate (Fuehrungszeugnis) is not a standard application document — you are not obliged to submit one unsolicited. BDSG Section 26: employers may only collect data that is necessary for the specific position. Mandatory extended clearance certificate: professions involving care of minors (Section 72a SGB VIII), public sector in sensitive areas, security positions. The standard certificate can be requested by anyone at the local registration office (Bundeszentralregistergesetz). Cost: 13 euros. The job description is sufficient for the application — you do not need a letter from the employer. Note: the clearance certificate is sent directly to you, not to the company.