Communication with Ariane was very easy, she confirmed and answered my messages quickly. She speaks German, English and Portuguese, so it's easy also for foreign tourists.
The stairs that other guests warned about in their reviews are not scary at all actually :) Ariane's apartment has a very good location, close to move around either on foot or with the subway/tram. The room was clean and cozy. If I go back to Lisbon, I would choose her place again.