The Immigration Office will check the requirements while processing the residence permit and will not issue a separate work permit. The work permit is part of the residence permit. Accompanying spouses are generally allowed unrestricted access to the German labour market.
Source of Funding
There are two main sources of funding – either through a work contract or through a stipend. Your income from a work contract is taxable and you will have to pay social security contributions. It may also entitle you to claim a German pension and unemployment benefits.
If your research stay in Germany takes place in the framework of a fellowship you may be exempt from taxation. It is certainly worth consulting the organization that has awarded the fellowship. Furthermore, you should find out whether the fellowship paid in Germany is subject to taxation in your home country.
Fellowship holders are eligible for private health insurance and in some cases for public health insurance, too. The International Office will give you further advice on this issue.
In addition, there are various German sponsors and foundations that offer grants to graduates, doctoral candidates, and professors that allow them to stay for an extended period of studying and/or research.
The EURAXESS Germany’s funding database: http://www.euraxess.de
A great overview about possible types of residence permits for scientists:
Visaerteilungspraxis bei Wissenschaftlerinnen und Wissenschaftlern aus Nicht-EU-Staaten
The Free State of Saxony welcomes visitors and new citizens from all around the world. The Ministry of the Interior issued some helpful information on visa application procedures and residence permits for highly qualified professionals:
AKZESS Ausländische Fachkräfte-Zuwanderung effizient und sensibel steuern Efficient immigration management for qualified professionals
A guide for international scientists at Max Planck Institutes provided by the Max Planck Society:
Living and working in Germany A guide for international scientists at Max Planck Institutes
Germans sometimes seem to behave strangely. With this handbook the Max Planck Society wants to facilitate the start of foreign scientists and their families in Germany:
How do Germans tick? Intercultural Handbook