For the reasons that didn't depend on us, we stayed at Costanza's new apartment in Corso Buenos Aires. The place is brand-new with a spacious and nicely furnished bedroom. The kitchen and living room are small and cosy. The apartment perfectly fit for a pleasant stay. The nearest metro station is within 1-min walk as it's located at the corner of the building.
All the check-in is done by Costanza herself who is a perfect host! She is really friendly and always ready to help with everything. Next time we'll definitely stay at one of her apartments.