Let me begin with the positives:
The flat is absolutely ideally located, mere minutes away from Châtelet-Les-Halles making it very easy to reach and is within comfortable walking distance of virtually all of the major tourist attractions. The flat is well stocked with all the cooking utensils, spices and equipment you could possibly need and is very bright and welcoming. There is also a massive collection of books, DVDs and CDs that have been made available to guests if you want to spend a relaxed afternoon or evening in.
Unfortunately there are also some drawbacks:
Most significantly I regret to have to say that the flat was, unfortunately, not well prepared for our arrival - dirty plates, glasses, pot and pans had been placed in the kitchen cupboards without adequate cleaning and the flat was just generally not particularly clean. A second issue is that there is very limited storage space made available to guests as virtually every inch of space in the flat is filled with books, CDs, DVDs and the host's own clothes - not a problem if you are staying for a short period and are content to effectively live out of your suitcase for the duration of the visit, but certainly not ideal if you are staying for a longer period.
Overall my wife and I enjoyed our holiday and no single issue was enough to sour the experience. It really can't be overstated how great the location of the flat is and if the issues that I have highlighted are of no concern to you I would offer a cautious recommendation of Cedric's flat in the hope that our experiences with the cleaning are an outlier rather than the norm.