Paradise City was the capital of the planet Nimbus III, established in 2267. Paradise City housed the representatives of the three governments in control of Nimbus III, the United Federation of Planets, the Romulan Star Empire and Klingon Empire.
The city was not very technologically advanced. It had basic houses and a bar, which had a communications panel. There were walls surrounding the city, with a front gate at which sentries could be posted.
In 2287, Sybok and the Galactic Army of Light captured Paradise City in an attempt to lure a starship from one of the three empires to use as a means to follow his quest for Sha Ka Ree. James T. Kirk led a team to subdue the group and rescue the diplomats, however, they had become influenced by Sybok and instead forced the team to take them to the USS Enterprise-A. (Star Trek V: The Final Frontier)
See also: Paradise