Élise & Sébastien are a company running multiple apartments in the city. Having that under consideration, I think there are a few things that could have been better.
Apartment: the flat is excellent and very new, bed linens, towels, toiletries are of good quality. It is a high floor with an elevator, which allows you to have plenty of light. However, beds are small (US full size, I guess, not the best of comfort), and there are not two bathrooms as posted but two showers and one toilet (worked well for us and is common in France).
Location: Paris is huge, but for tourism, I´d say the apartment is centered with respect to the main spots, which makes it far from all of them.
Service: It was really annoying getting dozens of emails from them requesting the exact time of arrival with a long list of instructions to follow, under the threat of having too many appearances that afternoon and that not following their instructions could let us wait outside. Fact is, we followed the instructions, told them hours in advance that our flight was 1h delayed and provided the exact arrival time and tracking number, called them as instructed when landed and... we had to wait. I should recognize after all these emails the situation got me out of my nerves and of course, this principle you may remember from a famous movie applied here: in France, the client is always wrong. So, it ended up being my fault.