The Forbidden City was on the Mid RimplanetLahsbane. It was the home of the mature Huhks, known for their tendency towards violence, and as such, off limits to offworlders for their own protection.
The city was built on a scale appropriate to the large Huhks, and as such had huge doors and windows. This was surprising to any offworlders that did enter the city as it seemed completely out of proportion to the diminutive Lahsbees more frequently encountered by offworlders.
The Forbidden City contained a treasure room that once contained tapes recorded by Yom Argo. Leia Organa and Dani retrieved the tapes, with Dani also stealing some treasure on the side.