Sample response for 2/sharing/get_file_metadata user do not have download permission

I'm not sure I understand exactly which scenario you're referring to. Can you elaborate? In any case though, all of the errors that can be returned are listed in the documentation:

https://www.dropbox.com/developers/documentation/http/documentation#sharing-get_file_metadata

The actual response response would be structured JSON, e.g.:

{
  "error_summary": "access_error/invalid_file/...",
  "error": {
    ".tag": "access_error",
    "access_error": {
      ".tag": "invalid_file"
    }
  }
}

Or, if you're interested in a successful result with a "false" permission returned, it would look like:

{
  "access_type": {
    ".tag": "viewer"
  },
  "id": "id:Hcd4PILNenwAAAAAAAAACw",
  "name": "hello.txt",
  "owner_team": {
    "id": "dbtid:AAALfOJvW_VA8-yeLzHQ5Pug2GR15Z4t8KI",
    "name": "TEST API Tester Team"
  },
  "permissions": [
    {
      "action": {
        ".tag": "edit_contents"
      },
      "allow": false
    }
  ],
  "policy": {
    "member_policy": {
      ".tag": "anyone"
    },
    "resolved_member_policy": {
      ".tag": "anyone"
    },
    "acl_update_policy": {
      ".tag": "editors"
    },
    "shared_link_policy": {
      ".tag": "anyone"
    },
    "viewer_info_policy": {
      ".tag": "enabled"
    }
  },
  "preview_url": "https://www.dropbox.com/scl/fi/vmn6wlojv52rnm51tmb9a/hello.txt?dl=0",
  "time_invited": "2017-03-27T18:31:52Z"
}