We recently combined 3 nights apartment with 4 night hotel...two different areas in Paris and both experiences were really good. I would however not necessarily recommend apartment rental for stays less than 5 nights...preferably rent for one week. Apartment check in and out is very different and they need more time to clean etc. For me there is too much paperwork, arrival and departure protocol for a short stay. Of course if you have need for multiple rooms or beds it could be good solution. I found that most companies were flexible for short stays closer to arrival if they have some "holes" in their calendar but I would assume better price would be for the 7 night stay. Paris has so many wonderful small hotels and apartments the search can be very confusing. We ended up renting from Haven in Paris and recommend them. Our hotel was Montalembert which I will be reviewing and has a wonderful location and very good service. We enjoyed both.