Charter cities are those given leeway to operate differently to the standard model set by various territories. There are hundreds of such cities in the US, including San Francisco. But while charter cities are fairly common, international charter cities are another matter. The idea, proposed in the late 2000s, was that new cities could be established in developing nations and operated by outside governments or organizations, with a completely different economic and social model to the rest of the country, as a way to supercharge development.
If "Nextpolis" goes ahead, it'll be the first bid to establish an international charter city -- albeit one with some tweaks -- in almost a decade, and the first to go beyond the planning stages.