Nathalie was very kind and flexible. Her apartment is really beautiful. There was nice furniture like a cozy bed and an armchair. We stayed there with 4 people, so one of us had to sleep in the little attic floor, which you can reach over a ladder. On the big table were some colorful flowers and fresh parsley. The kitchen is well equipped with coffee, tea and everything you need to cook a meal. Only the dishes are a bit few with just 3 forks and 2 knives. We liked that the room was very bright with lots of windows. From the balcony, you could watch the skyline of Rotterdam. The bathroom with lots of towels is located downstairs and very small. It's just like a toilet with an integrated shower, but that wasn't a problem for us.
If go outside, you are on a lively street with many shops and two tram stops nearby. There is an international atmosphere with mostly turkish people. The next supermarket is just about 20 meters away, where we found everything we needed.
All in all, I definitely recommend this place if you want to spend a great time in Rotterdam. We all agreed that Natalie's place would be the best apartment to live in for a group of students like us.
One last idea: For complete awesomeness there has to be a hammock!