apartment rental sites

We've used vactioninparis.com and been very happy with them.

My mother and I used Vacation in Paris as well and were very happy with our apartment and stay. I loved having our keys before we got there and it had everything it said it would and was clean.

I've used Vacation in Paris three times and have not had any problems with them.

I have used Homeaway elsewhere and VRBO many times, including Paris.

We have used VRBO and Homeaway many times with good results. I only rent places that have many reviews from former renters.

Vacation in Paris
Have now booked with them twice. Rented 74 and 249

While not for Paris, I've used airbnb many times just this year here and in Asia...awesome site...would recommend highly.

airbnb. Have used nationally and internationally. Practical. All good.

We used homeaway for Paris and got good results (but how to generalize from one example?). We've used it several times in the US, also good, and we're using it next month for two places in France. Airbnb also worked for us the one time we used it, here. I haven't heard of housetrip or 9flats, others have given good reviews to vacationinparis.

Can't speak for any but airbnb...used it in Boston, London, Paris, Florence, Villefranche, and for about 5 stops on my upcoming California trip...my advice - read all the reviews, look at amenities and what you want (laundry? wifi? free parking if needed?), look at the map and see where it is in relation to what you want to see, look at the street view if it's avail to see what the area really looks like...I've had really great stays and there are some great deals to be had.

AirBnB.com is really getting large, and it's going to be a big force to deal with in the future. My only gripe is they charge your credit card when reservation is made, even though it may be 6 months before your arrival. We had an incredible apartment recently in Halifax booked on AirBnB.com. They get your opinions of the property--as well as get opinions on you as a renter to pass on to future AirBnB property owners.
In some locales, we do better using Booking.com--the biggest accommodation website in the world. They don't charge your card until arrival.