The legal restrictions for working in Germany as international students are very strict - and should be considered before applying for a job. Students from Non-EU countries are restricted to 120 full work days or 240 half work days a year.

• More about jobs for students
  https://www.uni-kassel.de/uni/en/studium/kontakt-und-beratung/servicestellen/career-service/jobs-internships
  https://www.studis-online.de/StudInfo/Studienfinanzierung/jobben.php  (German language only)

• andhttp://jobboerse.arbeitsagentur.de
• useful information for students: "Jobben", Download on pages of Deutsches Studierendenwerk (german language only)