Regierungsbezirk (pronounced [ʁeˈɡiːʁʊŋsbəˈt͡sɪʁk], abbreviated Reg.-Bez.) is an administrative region on federal state level in Germany. The regional authority is called Regierungspräsidium or Bezirksregierung (District Government) and headed by a Regierungspräsident (District President).
The Regierungsbezirke do not pass any legislation. Within the federal state authority, they act as a mid-level agency mostly concerned with administrative decisions on a regional level for the affiliated rural or urban districts.
More information on the Wikipedia page .