If you intend to live and work in Aachen long term, then you will need both a residence permit and a work permit. Work permits are a more complicated process than residence permits and if you are outside the EU, their issue will depend on whether or not the job you are applying for can be filled by a German native, an EU citizen or any other person who is considered to have preferential treatment. The best route of entry into Aachen is with a job already in place, as the job marketplace is competitive. Work permits can be granted for specific jobs only, not work in general. You can become self-employed in Aachen if you meet certain criteria and get a work permit that way. If you are highly qualified or have critical skills, then your chances of getting work are greatly enhanced. Getting into the workforce in Aachen is not easy, and moving from job to job all hinges on the relevance of your work permit. Once in, it is a great place to live and work and not something that anyone could regret. If you are planning to move to Aachen as part of your retirement, then your pension will support you and the process will be easier, however even part time work requires the gaining of a work permit.
As with any city, jobs in Aachen are advertised on the internet and in newspapers. The main government body that is involved in unemployment and finding work is the Federal Ministry for Employment and Social Security. Aachen is a student city, so there are always plenty of applicants applying for jobs. Local advertisements are a good way of finding smaller jobs while employment agencies will have a comprehensive list.
If you are an expat living in Aachen, then the same rules will apply to you as to an expat in any other part of Germany. Currently the single person tax free allowance is 8,354 EUR (16,708 EUR for a married couple). Incomes from 52,882 EUR for a single person and a joint income of 105,764 EUR for a couple are taxed on a progressive scale, from 14% to 40%. There are a number of allowable tax deductions such as for children under 18, if in school and without earnings this age limit can rise to 27. Deductions from salary are made by both employee and employer and count towards four main benefit programmes for unemployment, health insurance, long term care and retirement.