What has been arranged if I want to take unpaid leave for free use?
There is no statutory regulation for taking unpaid leave. You should therefore not confuse it with the statutory regulations whereby you can stop your work in time to provide care, for example. If you want to take unpaid leave as an employee, you can ask your employer about the possible options. Please note that with unpaid leave your income will be lower and that this can have consequences for supplements, benefits, pension accrual and vacation days.
In your collective labor agreement, internal company regulations or employment contract you can check whether you can buy vacation days from your employer (á la carte system) and thus continue to pay for part of your leave, which also includes the accrual of employee social insurance schemes and possibly pension.