Kreisfreie stadt
The name kreisfreie Stadt (plural: kreisfreie Städte) is used for German towns that have their own government. This town government is independent of the government of the next-higher level of authority, the Landkreis. Today, most of the cities that have this statute, are big cities, with 100.000 people living there, or more. The concept grew historically. That means that there are big cities, with more than 100.000 people that do not have the statute. There are also some cities who have only taken a part of the responsibilities of a Landkreis (or Kreis). The smallest city with the statute is Zweibrücken. About 35.000 people live there. The biggest of these cities is Munich, with about 1.3 million people. Hamburg and Berlin are bigger. They are city states, though. The city state of Bremen (state) is made of two kreisfreie Städte, the city of Bremen, and the city of Bremerhaven, about 60 km to the north. About half a million people live in Bremen (1.5 million in the agglomeration), about 117.000 people live in Bremerhaven.
But not every big city with more than 100.000 inhabitants is a kreisfreie Stadt. Some of them, for example Recklinghausen or Göttingen (both more 120.000 inhabitants) are part of a Landkreis.
There are very few cities, who only took part of the paperwork from the Landkreis. Some of these are called Große selbständige Stadt (Translates to Big sovereign city). They only seem to exist in Lower Saxony. They are: Celle, Cuxhaven, Goslar, Hameln, Hildesheim, Lingen, and Lüneburg. Things like hunting permits cannot be delegated to the cities. Other things, like what to do with the trash have sometimes been delegated.
Similar concepts to that of the kreisfreie Stadt are Unitary authorities in the United Kingdom, or that of independent city in the United States.