[benjaminsuch]

In germany it's only 3 month if the employee has been in the company for 4 years. Until then it's only 1 month.

Edit: Both parties can of course negotiate a bigger time frame.

[lethef]

This is simply not true. At least in IT it's 3 months as soon as you're done with the probation period (which is usually 6 months). Not sure about the employer, but employees can cut this period shorter. The document is called Aufhebungsvertrag – termination agreement. I just think the employer has to agree to this.