Do I need to send diplomas with my application?
Yes, especially if it/they relate closely to the job profile or the skills required. There is no need to attach every diploma (e. g. from a computer course 10 years ago).
Should I supply references, letters of recommendation or proof of good conduct?
Testimonials that prove that you are an efficient, hard-working employee are a must to convince your potential employer that you should be hired for the job. (The testimonial is a certificate that every employee in Germany has the right to receive from their employer. The simple testimonial contains personal data and information about the type and duration of the employment, with no evaluation. The qualified testimonial also includes the output, qualification and official behaviour of the employee.) You must send testimonials and copies of your diplomas with your covering letter and your CV.
References and letters of recommendation are not widely used. Only in exceptional cases will a new employer contact your existing or previous employer.
For a job in the public sector, you will need proof of good conduct, available from your local police station. For other jobs, you will usu¬ally not know in advance if you need this. The employer may ask for it when you sign your contract.