The flat was amazing, very well located and well worth the stair climb. It was better than we expected, it looks better in real life than it does on the pictures.
The place is very stylish and has everything you need, nespresso, dishwasher, washing machine and oven. There's a fan that we used as we stayed when there was a heatwave, but when opening the balcony door and the kitchen window there was a nice breeze.
Internet worked when we were there, not the fastest but good enough.
There's a bakery around the corner that has very good croissants. Easy to get to Gare du Nord and CDG Airport. There are no curtains however, so do make sure to bring an eyemask to sleep! But great views of the water from the bed.