The apartment is pretty much as described - spacious, overlooking a quiet courtyard (with occasional sounds of distant sirens only, and some muffled talking and footsteps from neighbouring apartments), and nicely furnished in loft apartment style. It’s a short walk (about 10 minutes) from Gare du Nord, so not far to carry or drag luggage if arriving in and/or leaving Paris by train. Check-in was very simple: follow the instructions to the letter, and you’ll find your way in easily. Just remember to walk through the lobby and into the courtyard itself (it’s this lobby that creates the separation from the busy road outside, thus cutting out much of the traffic noise). Thomas is very responsive to any questions.
Use the crossing (watch out for cyclists!) and rue de Sofia opposite the main door on the road, and you’ll find several supermarkets. There’s a large Carrefour just across the next road (rue de Clignancourt), but while the store has lots of choice, the service is appalling. Instead, turn left on Clignancourt, and you’ll find a delightful and friendly boulangerie a bit further down for your daily bread, and immediately next door to that a smaller, much friendlier supermarket for other provisions.
Now, about the area; all I’d say is that if you are used to multicultural inner-city living, it won’t bother you much. If you’re more used to quiet suburbia or rural living, you may feel you’ve bitten off more than you could chew. You need to keep your wits about you, especially under the bridge at Barbès-Rochechouart Métro. However, within minutes of leaving the building, you can be in a neighbourhood far removed from this chaos (walk the same way as for the boulangerie on Clignancourt, cross the busy Boulevard de Rochechouart, and cut through to Place d’Anvers/Avenue Trudaine, and you’ll find yourself in a more upmarket area bordering Pigalle - with a lovely food market on some days/evenings around Place d’Anvers).
So, to sum up, a spacious, fairly quiet apartment, and within easy walking distance of a decent food market and neighbourhood. If you can cope with the bit of chaos between the two, this could be the ideal place for you to stay!