This apartment was far better than we had hoped - location is superb with the Louvre over the road, McDonalds wifi at the end of the block if the apartment wifi is too slow for you, and right next to the metro station for Line 1 which is the most useful for getting around. We had the place for a week, which wasn't enough, and we are already planning next year's trip to the same place. Can't recommend it enough! It was great also that the apartment is empty, not full of someone's stuff, as we tend to spread out over all available space and everything would have got mixed up. The kitchen is great for family dinners (for three nights my brothers were there as well so we had four couples and one 7-year-old) and access to the apartment is easy even though there is no lift. It is very secure. Bring earplugs for sleeping if you are a light sleeper - there has to be some downside to being so close to everything.
Getting from the airports is also very simple - train RER line B, change at chatelet-les halles for Metro line 1 towards La Defense and get off at palais royale. Too easy!!