[circonian]

Try this:

local zoneIndex, poiIndex = GetCurrentSubZonePOIIndices()
if poiIndex then
    local normalizedX, normalizedZ, poiType, iconPath = GetPOIMapInfo(zoneIndex, poiIndex) 
    if iconPath:find("poi_city") then
        -- in a city
    end
end

Should work in any language.