Complex sentence: Since 1947, the former city area is administered in 23 special wards that have in several steps until the year 2000 achieved a status fully on the municipal level themselves; but the Metropolitan government continues to exert some municipal authority, e.g. for fire protection.
Split into simpler sentences: Since 1947, the former city area is administered in 23 special wards. In 2000, they were formally recognized by law as local public entities on the municipal level; but the Metropolitan government continues to exert some municipal authority, e.g. for fire protection.