Gillian's place is exactly per the photos. It is small-ish but Gillian manages to make it doable for even a large group via the considerable bedding options in the small loft. That being said, it is a small apartment so groups of 4+ are probably best as tight family or students. We were three but the third was a baby - no crib available. As a result, we didn't use the upstairs loft and, instead, slept on the sofa/bed with the baby in her stroller. Gillian did let us know that there was no crib so that isn't a criticism. Still, for those traveling with a baby, it's worth knowing.
The apt is in a great area. This part of Paris is well known for being colorful so it has a variety of establishments and people that you wouldn't find in the Triangle d'or. If you're expecting sterile Paris (relative to, say, Berlin), you won't find it in the Marais. However, if you're looking for tremendous variety of food and cultures only steps away, this is a great find. While the price is great, you still need to factor in the cleaning fee which seems a high for such a small apartment.
The only real draw back to the apartment was the fact that the laundry room is actually shared by this apartment and the one adjacent. While you can lock your laundry room door, making it in accessible by inhabitants of the other apartment, it felt weird. If you chose to use the laundry room, you could find yourself interacting with the other apartment resident, for better or for worse. Additionally, while apartment rules forbid use of the laundry in the evening hours, who knows what limits are on the other resident/renter/Airbnb'er. In the early evening, before heading out for dinner, we had to listen to the laundry running for a couple of hours (European laundry/dryer take a long time). This wasn't a major issue for us but one that could be important for someone who is security conscious or doesn't like the idea of apartment noise induced by neighbors.
Overall, we were satisfied with the apartment and Gillian's hospitality.