.berlin is a proposed GeoTLD in ICANN's new gTLD program. The proposal was one of the first and most prominent gTLDs, specifically GeoTLDs, that began circulating as a possibility in the early-mid 2000s as a possibility should ICANN decide to expand the root zone with new gTLDs.
Historically, there are two main entities that have expressed public interest in running .berlin, DotBERLIN and Unite Berlin; the former received government support and was the only applicant. Its application is a Community Priority Application.
With new gTLD discussion happening in ICANN, Dirk Krischenowski and Alexander Schubert founded DotBERLIN GmbH & Co. KG in 2005; at that time ICANN's new gTLD application process was expected to begin in 2009. This process took longer to develop and was finally approved in June, 2011. Because of this delay, and the fact that dotBERLIN was prepared for a 2009 launch, they have asked for special consideration from ICANN in the delegation process. Specifically, DotBERLIN has asked that "One extra point in the Community Priority Evaluation should be given if the organization behind an applicantion was already established before the approval of the new gTLDs program by the ICANN Board on 26 June, 2008, or before the first communicated application window in March, 2009." That concession was not made by ICANN.
The reason dotBERLIN asked for such special consideration could be due to the fact that specific threats to their proposal have appeared. That is, Minds + Machines launched a Unite Berlin initiative, which is itself lobbying for the .berlin name space, some 6 years after dotBERLIN had already declared its intentions.
The community has been defined in conjunction with the city to include only those individuals and entities that have a verifiable presence or connection to the city of Berlin. Registration will require verification of one of the following: "their residence or second home, office or place of business, a branch or permanent establishment in the City of BERLIN, or; a contact listed in the Whois database with a domicile in the City of BERLIN, or; other appropriate proof e.g. the certification by an employer to enroll at a school or college, or birth certificate."