We really like to stay in Lehna's apartment.
The location is excellent: next to Sorbonne University and in a walking distance to main attractions, lots of restaurants, supermarkets and 3 min away from metro.
The building is old and does not have an elevator, so you need to use a ledder . The apartment is on the 5th floor. For us it was not a problem.
The apartment has 1 bedroom with a double bed and another room with kitchen and chill zone (tv+ sofa). Also there was another small room with Lehna's stuff. The coolest thing is a balcony with a wonderful view. You can even see a little bit of Eiffel tower.
No problem with Wi-FI and hot water.