To stay at Catherines apartment was a very good experience. It is located in the 20th arrondissement, so it's still in the first zone, which makes things easier and cheaper when it comes to usage of public transport. It's a small and cosy apartment, but totally big enough for 3 persons, especially when you spend a lot of time in the city anyways. We never met Catherine herself, but everything (e.g. to get the key) was very well organised. I totally can recommend to stay at Catherine´s - we had a great time there! :)