Sevastopol is a city on the Black Sea, located in the southwest of the Crimean Peninsula—a territory disputed between Russia and Ukraine as a result of the 2014 Crimean crisis. It has been under the de facto Russian control since March 2014, when it was incorporated into Russia as one of its federal subjects, with a status of a federal city. Being a disputed territory, Sevastopol has two sets of laws governing how its administrative and municipal divisions are set up. Under both Ukrainian and Russian laws, the city is administratively divided into four districts.
Under the Ukrainian laws, the districts have both administrative and municipal status, while under the Russian laws the districts are purely administrative and have no further divisions. Within the Russian municipal framework, however, the territory of the federal city of Sevastopol is divided into nine municipal okrugs and the Town of Inkerman. While individual municipal divisions are contained within the borders of the administrative districts, they are not otherwise related to the administrative districts. The borders of the municipal okrugs are unchanged from the borders of the municipalities which exist under the Ukrainian law.
More information, including lists of subdivisions, on the Wikipedia page