Hi, i too have had difficulty finding accomodation in paris, at one point i had to settle for short term (weekly accomodation), i did eventually find a nice studio in Montparnasse. Im now in my 2nd apartment (i lived in paris before), if i can give any advice, its that your looking the best way, ive always refused to pay the agency fees (maybe because i once worked in real estate
. There are plenty of sites out there, but its just a case of phoning and "clicking" with that landlord. have a look at http://expatfrance.wordpress.com/
. there are classifieds on there, just a quick search and it came up. there are many others too , goodluck!!