We really enjoyed staying at Marie and James' apartment. Marie was very hospitable and welcomed us at the apartment upon our arrival and they were so nice to gift us a bottle of wine and Orangina drink (it was so good and our kids loved it so much that we bought several more bottles during the trip!) Our flight arrived in the morning and we were afraid we would have to carry our two big luggages around until standard check-in time but Marie and James were kind and flexible enough to allow us to check in at our convenience. The apartment was spacious compare with other places we looked at in AirBnB and hotel, and very comfortable and have a real Parisian and home feel, and did not feel generic at all. There are two ample size bedrooms and a sofa bed in the living room, plenty of windows so very airy, the weather was very cold and rainy outside but the apartment was plenty warm with the heaters, and the bathroom actually have a bathtub! (Most places we reviewed in AirBnB only have showers.) The apartment has an artistic feel with all the old table lamps, tons of books on the shelves, arts on the wall, and the antique-ish mirrors and other decors. To get to the apartment you do have to go through a short but dark corridor then through the courtyard (we eventually figure out there is a light switch), and then walk up a set of short but narrow stairs. Also, from inside the complex, to open the front gate to go back out to the street, you need to press a button the wall (it took us a good 3 minutes to figure out how to open the front gate before figuring out that we needed to press the button!)
As far as the location, it is really perfect! First of all, we bought a Navigo Decouverte Pass that allowed us to travel on any public transportation for the week, including all buses and Metros, RER train from CDG to Paris, RER train from Paris to the Versaile, and even the tram that take you up the hill to Sacre Coeur. The price of the Pass almost paid for itself just for covering the trip on the RER train from CDG and to Versaille, and we were free to explore without having to worry about paying separately for each trip on the Metro. The location is a very short 3 minutes walk down the cobble paved road to the Abbesses station (Green line #12). This is our main station. However, when you are arriving from or leaving to CDG, you would take the RER B train into Paris which stops at the Gare du Nord Metro station and unfortunately Gare du Nord does not connect directly to the Green line #12. Instead, you would connect from Gare du Nord to Blue line #2 (La Chapelle) and travel to Pigalle station (3 stops). From Pigalle, it is actually a 10 minute walk up to Marie and James' apartment, or you can choose to connect to Green line #12 to go up one stop to Abbesses (but might be less effort just to walk the extra distance). One thing about the Abbesses station - always take the elevator in the station because there are many steps to the actual train platform. The location is in southern part of Montmartre (we didn't feel unsafe at all, in fact it felt very "local" and people were friendly. We did get pickpocketed sadly.....but it was in the Saint Germain/Odeon area inside the Metro). We found a tons of great restaurants and excellent bakeries, and it was near Sacred Coeur. (Excellent bakeries include award winning Au Levain d'Anton, and Pain Pain, and we had excellent food at Bouillon Pigalle (line out the door until late, atmosphere was fantastic especially whenever someone has a birthday, all lights are turned off and the entire restaurant sing happy birthday song in French), Le Potager du Pere Thierry was excellent (foie gras was great as with the duck breast and the fish), and Le Consulat (escargot and mussels and the duck breast were awesome). From the Abbesses station (or Pigelle), it is really a short Metro distance to all of the main attractions. Our frequent stop was from Abbessess down to Solferino directly on Green line#12 which connects with the Musee d'Orsay, and from there, you can transfer on line RER C to Eiffel Tower, to Versaille, or to Notre Dame, very convenient.
As for the pickpocket experience, here are some advices (lesson learned). The pickpocket gang always works in pairs. One would try to distract you while the other would get into your pocket or your back pack. There were several attempts on pickpocket on my family and we always witness another person's small bag being blatantly taken by another, and they all happened on the Metro. Don't carry your passport or expensive things on you when you go out - keep phone and wallet in your front pocket and not in your backpack. Make sure backpack is always completely zipped up. Avoid standing close to the train door (they love to grab and run out the door). If someone is trying to be friendly, or brush you and then apologize, it might be a distraction ploy. Ignore and be on guard and they won't pursue further. Also, be aware of people with clipboards approaching you for donation to charity (like for the deaf) - ignore and walk away. Also there may be people approaching you trying to give you "free" friendship bracelet and forcefully try to put on your wrist - walk away as quick as possible. Just some helpful advice and you will enjoy your trip!
Thank you Marie and James!