My suggestion is that you do a little searching. There are a lot of apartments out there! You might start here:

www.vacationinparis.com
www.vrbo.com

Once you find some apartments that you like, post the links on the forum - it's likely that someone here might have stayed in them and can offer specific advice.

Trip Advisor also has reviews of many Paris apartments. Bonne chance!

What do you mean by "low cost"? What time of year? Will you take a studio with one bed and a pull out sofa or futon?

We had great luck with www.parisaddress.com in 2010 (a one-week rental for two, in April). Their site has apartments in every arrondissement, in a wide variety of price ranges and sizes. We booked online and paid with a (US) credit card with no problem. They had someone meet us at the apartment to hand off the keys, who gave us a tour (in English)including how to use the dishwasher and washer/dryer, etc. I think they offer pick-up service at the airport and major train stations for an added fee, though we opted to take the RER in from deGaulle because we didn't have many bags and were comfortable getting around.

Search on "Paris apartment rentals" on this board and I'm sure you'll find plenty of other recommendations, as well. If you have not done the apartment thing before, you'll love it!

parisbestlodge.com

safe careful many scammers individuals may not legally rent

use only agencies never wire money always pay as little as you

can with CC... Marais was my fav for this last

MANY fakes owners reviews on crraigslist tripadvertizer verbo

So Caveat Emptor... no clue bout your budget but 3

cheap central places for me www.mije.com Hostel best

www.hotel-collegedefrance.com

Lastly recently snagged a 4 star last week on Hotwire.com

for 112 euro/nt their secret Lovre/Vendome Hotel

The Novotel Les Halles like 70% off have a look there

for something super nice and well located.

Check out ownersdirect.com and home away holiday rentals. I have used both successfully.

This company has 3 apartments in the same building as the office, but it is in the 2nd. They are nice and very inexpensive. My kids stayed there last February. The company was great and worked with us in a very professional manner.

Scroll down to the bottom of the page where you'll see the green buttons.

http://www.bluemarble.org/

dave