Can I estimate the audience size given the city and the language?

I need to mimic the behavior of the targeting selection screen, just make it simpler, limiting the choice to few languages and a few hundred cities, see the picture of the original screen below. I tried calling

curl -G  \
  -d 'targeting_spec="{"geo_locations":{"countries":["BE"],"zips":[{"key":"BE:1000"}],"locales":[{"key":"1003"}]}}' \
  -d 'access_token=TOKEN' \

http://ift.tt/1BRnR4f

but I get the message

{
  "error": {
    "message": "The entity backed by id ENTITY_ID cannot be seen by the viewer with (ViewerID 0, AccountID 0): DENY_RULE:InlinePrivacyPolicy:AlwaysDenyRule:4 (EntID: ENTITY_ID)",
    "type": "OAuthException",
    "code": 1
  }
}

Should I ask for more permissions from Facebook? And how? I am just trying to build a simple website app.