My husband, 2 daughters and I stayed for 5 nights. The apartment was surprisingly larger than we expected and the views from this flat were fantastic. Due to the layout of the apartment, you could always get a nice cross breeze when the windows were open, so it was never hot or stuffy.
Overall, It was clean, bright, well maintained and fully equipped with everything you might need. The bed up in the loft was sooooo comfortable. We were concerned that it would get hot in the loft, but the sky window above the bed provided cool comfort. The kids (9 and 11) were also comfortable on fold out single foam beds in the living room.
We really enjoyed our breakfasts in the sunny, bright kitchen. The bathroom was a decent size with single sink, bathtub/shower and a wardrobe to hang your clothes. There was even a towel warmer/dryer rack which we thought was a very nice touch.
We really enjoyed the neighbourhood which had everything - cheese shop, deli, butcher, seafood shop, a few French bakeries, a couple of traiteurs (a food shop offering delicious ready to eat / take out salads, meat and seafood dishes), fresh produce store, regular supermarkets, bistros, etc.
The apartment was conveniently located between two major metro stations (Republique & Oberkampf) and within walking distance to the hip/trendy Marais district.
But what really sold us on this flat was the owner. She was extremely efficient, organized and communicative. Before leaving for our trip, she had provided us with maps, directions on how to get to the apartment, restaurant recommendations, list of important numbers, etc.
We enjoyed our stay at 19 rue Ternaux and will definitely be back!