Unlike in the Netherlands, a permanent contract is the norm in Germany. A temporary contract is allowed, but only for a period of two years. Longer is only allowed if you have a special reason (in German: Sachgrund).
For example, because it concerns a project or the replacement of a sick or pregnant employee. In both cases, the agreement that it is a temporary contract must be recorded in writing in advance. An early termination of a temporary contract is only possible if this has been agreed or if it is stated in the applicable collective labor agreement.
In order to compete on the German labor market, it is therefore advisable to work with permanent contracts as much as possible. In general, this does not have to be a problem, as you can work with a probationary period of 6 months and dismissal law in Germany is in many cases considerably more flexible than in the Netherlands (see point 4).