This is a great place to stay in Paris. Very centrally located, lively, safe and full of cafes and restaurants. It is next to a University, only a few blocks from St Germain de Pres and the Seine and only a few more blocks from Notre Dame. It took me only 20' to walk to the Marais, but you can also take the metro (Jussiu) that runs at literally 5 meters from the apartment. The apartment itself has all the elements you need for a comfortable stay: excellent light, good space to work, hot water with good pressure, kitchen stuff (microwave, toaster, coffee maker, etc), washing machine, lots of books, decent wifi, even an 'echo' to call Alexa! It has a small closet and only a couple of empty shelves, but it is a large apartment with lot of spaces and surfaces to deposit stuff.
Its main cons are in the airbnb description: 1. the metro runs below and makes noise, 2. it is 3 floors up through a narrow spiral staircase, no elevator. I was not bothered by the metro since it stops at midnight and during the day you almost get used to it as white noise (or you can use earplugs...). It can also be a pro since it deposited me a few steps from the door when I came from the airport and it is there to go anywhere in Paris. The stairs are a good exercise after the Parisian meals, but you have to be able to handle them.
One more thing that can be a pro or a con is that the toilet is at the entrance whereas the shower and sink are inside (next to) the bedroom. If you are a couple it might be useful as both can get ready at the same time. On the other hand, if you wake up at night, you have to walk through the living room to get to the toilet :-)
Overall it is a good value for a stay in Paris.