I didn't meet Tatiana, but her father, who is really lovely and speaks English very well!
Tatianas place has a great location in a quiet neighbourhood, only a 20 minute walk to the Eiffel Tower. There are grocery shops and restaurants just outside of the front door. I've never stayed in this area before, but it's quite nice compared to many others. The apartment is small, but suitable for 1 or 2 people. The kitchen is small, but has everything you need (incl dishwasher) apart from a microwave (if you are that way inclined)
The bathroom is good, there's a washing machine, water pressure really good, bathroom door very squeaky.
Living space is nice. I can't remember seeing a TV there, but that wasn't an issue for me. The bed, sadly, is not amazing if you weigh over 70 kgs... I could feel the slats through the mattress.
Balcony is small, but great. If you lean over the railing, you can see the Eiffel Tower;)
Pros: Location, water pressure, balcony
Cons: Kitchen/bathroom could be cleaner, bed
I'd stay here again.