For cultural district funding, there's no one centre where you go to apply to be a cultural district. Depending on your business, what you would do is to seek support from many levels of government and many funding programs in government to be able to animate the work you want.
If you're an arts presenter, you'd go to the Canada arts presentation fund. If you want to build a building, you'd go to Infrastructure Canada to get the core support. If you are looking to enhance your artistic work, you would apply to the Canada Council for the Arts.
The answer is that there is a lot of opportunity and a lot of federal programs, as well as the support that each of the arts councils within the provinces can provide, depending on what the project is.