Deals, descriptions, photos, stars, comparisons are why I like to do my research on internet booking pages.  A few I’ve been using lately:

http://www.hotelscombined.com
http://www.booking.com
http://www.tripadvisor.com

Some good deals during this shoulder season:

Hotel Monceau Elysees
108 Rue De Courcelles, 17. Batignolles-Monceau
$75 best deal
http://www.hotel-paris-monceau.com

Victoria Hotel Paris
2 Bis Cite Bergere, Faubourg-Montmartre
$85 best deal
http://www.hotelvictoriaparis.com/fr/

Quality Hotel Paris Orleans
185-187 Boulevard Brune, 14. Montparnasse
$90 best deal
http://www.paris-orleans-hotel.com

Hotel Fontaines du Luxembourg
4 Rue De Vaugirard, 06. Saint-Germain-des-Pres
$142 best deal
http://www.hotel-luxembourg.com/pages/hotel.html

Hotel Chaplain Rive Gauche
11 Bis Rue Jules Chaplain, 06. Saint-Germain-des-Pres
$138 best deal
http://www.chaplainparishotel.com

Hotel Observatoire Luxembourg
107 Boulevard Saint Michel, 06. Saint-Germain-des-Pres
$168 best deal
http://www.observatoirehotel.com

If you contact the hotel directly, sometimes you might get even a better deal. Almost all hotel staffers these days speak (or attempt) English.  Start with the booking sites.