It is two principles, in particular, that govern the interactions within a ministry: Each unit has a distinct remit assigned to it (division structure), and the individual units communicate and operate in keeping with the reporting line, meaning that, as a rule, communication takes place via the superior level instead of directly (hierarchical principle).
The Joint Rules of Procedure of Federal Ministries (Gemeinsame Geschäftsordnung der Bundesministerien – GGO) refers to the division as the key unit within the structure of a ministry. The division is the first decision-making authority in all matters assigned to it within its area of competence. The organisational unit above it is the directorate-general or directorate.
To carry out certain duties, especially with regard to the management of the federal authority, organisational units with staff functions, known as staff units, may be set up. Divisions and the higher-level directorates-general are the working level and directorate-general level, respectively; the positions above those make up the top-level management.