Charles and Anne's place is in a safe locality in Paris. We felt safe while returning to their place late at night.
It's in close proximity to a grocery store and also in walking distance to several metro stations and major train station of gare du Nord.
Though it won't be much of an issue but didn't find the place that comfortable enough for a family of 4 adults. Also you will have to climb stairs to the third floor, so it will be quite a work if you are with a lot of luggages. Place is equipped with all modern amenities.
Charles is a kind & generous host and was prompt to revert to any concern I had.