When using the bulk feature to download data containing special characters, the API call GET/bulk/{id}/{objectName} should have the content-type manually set as application/json;charset=UTF-8 in the application calling the bulk endpoint. Here is an API call example Itha retrieved the correct data containing special characters: 

curl -X GET \
  https://api.openconnectors.us2.ext.hana.ondemand.com/elements/api-v2/bulk/{id}/{objectName} \
  -H 'Accept-Encoding: gzip, deflate' \
  -H 'Authorization: User *****, Organization *****, Element *****' \
  -H 'Content-Type: application/json;charset=UTF-8' \
  -H 'accept: application/json' \