Pros:
The apartment looked exactly like the pictures given (at least to my eyes). So, you can accurately judge whether you like the interior or not, just by looking at the pictures. (Personally, I quite liked it.)
Location is great, as it is located in the 1st arrondissement where there are lots of shops in the area, and it is also very close to the Concorde metro station (about 300 meters, if I recall correctly) and to the Louvre.
The complimentary daily cleaning provided was gold! I stayed for 5 nights and I returned to a cleaned apartment with fresh towels and made beds every evening. I really like that the cleaning staffs made the extra effort to ensure that all chrome/shiny items (such as shower heads) were spotless. They also cleaned the dishes.
A washing-dryer machine was provided.
Nice floor heating in the en-suite bathrooms.
Sweets/candies/lollies, Oreo cookies, tea bags, coffee pods, and beverages were complimentary.
Complete kitchen and dining wares including tiny espresso cups were provided.
The apartment was quite, other than the occasional footsteps and chatting I heard from people walking up and down the stairs in the building.
Good, very responsive smart TVs. (Many "smart TVs" are sluggish/laggy but the ones in the apartment are not.)
Cons:
There are no full-length mirrors in the apartment.
You get two European square pillows only for the sofa bed (actually, I think there are two sofa beds but I only used one), and they were too flat for me, so I had to stack them up. It would have been nice if they had provided king-size or regular pillows as well.
I couldn't find any decent supermarkets in the area. All grocery shops I found were mini markets.
You get the view to the unroofed area in the middle of the building and it is surrounded by walls. In other words, you don't get any good view at all from the apartment windows.
The floor heating in the en-suite bathroom with white marble tiles didn't work as good as the floor heating in the other bathroom.
No floor heating in the toilets.
The marble coffee table looked to be of good quality, but there were watermarks or spots possibly left by irresponsible customers.
Overall:
The cons I found are nothing worth worrying about. My 5 nights in the apartment was very comfortable.