If you come from one of the 'old' EU countries and want to work here, you will receive a residence permit. Residents of the 'new' EU countries have to apply for additional permits.
If you come from a country outside the EU and want to work here, you need residence and work permits as well, and maybe a visa.
As soon as you start to work in Germany, you are also liable to pay tax in Germany.
Service for our customers:
We will register you with the relevant authorities, provide support in obtaining your work permit, look after your residence permit and will apply for an income tax card for you.
Our Authority Package is certainly a good option.