Wonderful location! An surprisingly quite. This is on the south shore of the river and IMO the best side. It's a quaint area with tons of shops and restaurants which really had a great Paris vibe. The apartment is small yes, but it doesn't claim otherwise. Some people have complained about the clothes washer and/or running out of hot water in the shower. We didn't have problems with either, even with 4 people. Just don't expect a long relaxing shower. There is no AC but that wasn't a problem when we were there. The kitchen looked stocked that you could cook in there, but we didn't cook anything anything while staying, other than microwave some stuff. The fridge was perfect size for our leftovers and sodas. When you go up and down the stairs, there are two illuminated light switches which activate a timed outside light for the apartment's exterior door which is nice for coming in after dark.
Space is tight in the apartment, so minimize suitcases to reduce clutter. We had lots of luggage which took up valuable space. This was our fault and due to our unique circumstances. 2 or 3 carryon size bags wouldn't be a problem.
If you're using Google Maps to use public transportation, try using the "prefer bus" option, especially if you have lots of luggage as finding a lift/elevator down into the metro and RER train lines is challenging. We found it more convenient to catch the bus at the nearby bus stops rather than deal with the stairs of the metro/train. Metro and trains share the same stations, just one set of rails is below the other. "Metro" is your typical city subway and uses numbers for their lines. "Rail" or RER trains are lettered. Don't be scared if you see an airplane symbol next to the B line. You don't have to go to the airport, it's just the line that does eventually go there. As long as you travel within zone 1, you use the same "t+ ticket" for both metro and RER.