there is one week in Paris, either in Sep or Oct that according to a paris tourist office staffer said was one of the worst of the year to find hotels - the Paris Fashion show i believe and perhaps this is that week. Yes 11 euro for that is no bargain, - unless most things else are booked.

I just checked the hotel listings on france.com, and for the dates Sept 20-24 there are still some good hotels in the Latin Quarter with availability. I didn't check other neighborhoods. Hotel de la Sorbonne (2 star) starts at 60E, Abbatial St. Germain (I've stayed there, the staff is friendly and the location is great), a 3 star, starts at 85E I think, I forget exactly. All the hotels listed there have customer reviews. Also cross-check with tripadvisor.com. You can book via france.com with instant confirmation, or go directly through the hotel.

You can also try venere.com They show a number of hotels in the llth for under 70 euro per night. They are two stars, but we stayed in the llth on our first trip to Paris and found it very easy to get to everywhere from there. There were two metro stops, Oberkampf and Voltaire (I think) and the Boulevard Richard Lenoir has a fantastic market that relocates itself at different places along the boulevard throughout the week.

Look at both two and three star hotels and try to think "location, location, location"

If you want an hotel in Latin Quarter for these dates, I found the Hotel Timhotel Jardin des PLantes to be available....115€/night...
You can see it on http://www.h-jardin-plantes.com
Have a nice trip!

Personally I would stay in the Latin Qtr...
In 2000 I went to Paris with my neice and stayed in 5...yes I said 5 different Holiday Inn's. All were clean most were so far from city center not worth the savings...but all of our rooms were tiny !!

The reason for 5 Holiday Inn's...well it was a cheap trip on a budget. My neice works for Holiday Inn Clearwater and we got the rooms for $24 US per night only thing was since we were staying on the comp rate no one hotel could accomodate us for our entire stay, hence the moving around. At first we thought well...that's OK after all the rooms were cheap so for that price we could suffer a little inconvenience... NOT.....After that experience I don't care if I have to pay $200 a night....I will never do that again nor stay at any one of those silly Holiday Inn's in Paris. This may not be true of all of them and at home I know that's not true but I for one will not take that chance again.