As far as I know, when one studies in Germany, then they give him or her one year visa to search a job.
 
My question is: If one finishes has studied in Germany and also has worked for lets say one or two years afterwards immediately in Germany (as postdoc), would they also give him or her such a residence permit to find another job? Assume that he or she has vever used this mentioned residence permit (has found the first job at the first day after finishing studies). 

By the way, is Arbeit-sucher visa for one year or more?

Any help would be appreciated.

Sara

It is only possible to apply for the permit for recent grads (§16 Abs 4) after graduation. It is not possible to change your status from §18 to §16 Abs. 4.  

Any Other ideas or experiences about this? It sounds a bit strange not being able to stay to search a job for a graduate just because he or she has been working for a while.

Someone I know could extend his/her visa but he had to show the authorities that he was paying his health insurance and was able to support himself (bank account statements).  They calculate the number of months you can stay depends on the amount of money you have in the bank.

Why do you think it is strange? §16 Abs 4 AufenthG was introduced to provide recent grads (Absolventen) a chance to stay in Germany after their studies to find their first job in Germany. The authorities assume that once foreigners have managed to gain work experience that they are integrated into the labour market.  

If you want the official opinion of the ABH Berlin (the largest ABH in Germany), I suggest that you read their VAB for further info (16.4.5).

Are you talking about §16 Abs. 4 for graduates of a German university or §18c for foreign graduates of foreign universities?

Graduates of a german university.