The apartment is nicely sized. We traveled with three kids (11, 7, and 5). They slept on the sofa beds. We kept them as beds the whole time and they worked well for relaxing in front of the tv. The location is noisy if your not used to the sounds of the city. It’s a busy road since it one of the main roads that heads to two big rail stations. So you get lots of sirens and horn honking. We slept with the windows open and our kids slept through the night-but they are hard sleepers.
You’re right on metro lines 4,8, and 9. So if you take the time to learn how to navigate the metro you’ll have no problem finding your way through the city. The cars are often full so I don’t necessarily recommend hauling lots of luggage on the metro, regardless of where you stay.
Check in is super clear and easy. Parisian vibes and lots of light and breeze if you open up the windows. We were there on a 100 degree day and it was hot, really hot, but the breeze helped.