Would absolutely 100% recommend Sophie's accommodation if you are after a simple no frills base for a visit to Paris. Less than 5 minutes walk from Gare du Nord so ideal if travelling by Eurostar. Nearby metro stations but a lot of the main attractions are walkable (90 mins to Eiffel Tower, 60 to Arc de Triomphe, 30 to Sâcré Coeur & Montmartre). Superb boungerie/patisserie just across the road where you can eat breakfast (including tea, coffee and a delicious hot chocolate) 'en place' or grab and go. Several bars and eateries too at reasonable prices given it is Paris. There's a small supermarket on the corner with pretty much everything you could need.
Sophie provides tea and coffee making facilities in the room, there's a bathroom with bath, overhead shower and sink next to the bedroom and the WC is just across the hallway. Hairdryer and fan also available. Oh and wi-fi of course. The bed is really comfortable and it was probably only the exceptional heat that meant we didn't sleep as well as we might have done (arrived in 42 degrees and it didn't drop below 25 overnight for the 3 nights we were there).
Unfortunately Sophie wasn't around when we stayed but her husband Alain made us feel very welcome and was happy to answer any questions we may have had.