Everything was perfect ! Carmen and John are really great hosts ! They had snacks for us when week-end arrive (with american cheese because we're French, how could you do better than that?), everything for breakfast and a lot of information on the things we can do in Chicago. It was very easy to communicate with them and they know a lot about the city. The apartment was very nice as well, and they had prepares everything for us.
We highly recommand to stay at their place if you're going to chicago !