More Specifically, once you arrive at your home city, go find your new house. Once you Enter, there will be someone there who starts you on a series of quests. DO THEM. Once you complete all of those, you will essentially be "flagged" to be able to click on that sign everyone has mentioned and get the citizenship application, which gives you the quest to do a task for citizenship, which when completed, allows you to be ready for the Instanced event that you need o complete to become a citizen.
I have done this with Fighter, Mage and Scout class characters in Qeynos. The basic structure for all these is essentially the same.
So, go get your house/hovel and do those quests.