We just got back from our short break in Paris. We (a family of 4) absolutely loved our stay at Marie's and Aurelien's apartment. The location was just perfect, we didn't even have to use public transport: everything is a short walk away (Louvre is 8 minutes walk, Eifel Tower - half an hour walk). Absolutely lovely restaurants 1-2 minutes away (our favourite was Café de l'Empire, their pasta, chicken and duck dishes were superb). The apartment was on a smaller side, but, considering how central it was, it still had two floors so we could chill while kids went to sleep. There is a bunk bed where kids slept, and a comfortable double bed for adults. There is a small convenience store just across the road, and a big supermarket 10 min walk. The place was very quiet, there was no noise at all so the nights were peaceful.
On our last day our train was in the late afternoon, and I asked the hosts for a late checkout at 11, and Aurelien responded that we could stay till 12 :) . That was greatly appreciated as we got a proper rest before heading back to London.
Overall, we would definitely stay at this apartment again when back in Paris! Highly recommended!