First and foremost, I must thank Andrija for his flexibility. My arrival was postponed for more than 8 hous and my host didn't make any issue about it.
The appartment has a support location : nearby the city center, the public transport and no loudly citynoises in the night.
There were not many questions to ask or answers to give because every thing was well explained on the site of Airbnb.
Top location in Vienna !!!