Zied welcomed me at the apartment building (and actually he allowed me come earlier than the initially arranged time) and showed me around the flat before leaving me with the keys. The space is clean and perfectly adequate for 1 person or a couple. The kitchen is a bit rudimentary (2 burners; no microwave), but it's enough to do basic cooking during your stay.

The flat is within walking distance to supermarkets and restaurants, as well as to a streetcar stop ("Servette"), where streetcars no. 3, 11, 14, and 18 stop (a route map is available on TPG's website); it's also possible to walk to the main train station (Cornavin) within ~20 minutes. I would happily stay here again!