My favorite place to give to is Emmaus, a homeless shelter with a facility for internet and education for homeless people, right in the center of paris: chatlet.
Emmaus is now collecting old cell phones. You can give your old cell phone in all French FNAC stores and they will be refurbished in Les Ateliers du Bocage (a structure that helps people with no job to learn a new job). Each 3000 cell phones package will give one new job at the Ateliers du Bocage. Refurbished cell phones will be sold at a very low price for African people or homeless in France. Emmaus France also plans to open a refurbished center of old cell phones in Burkina Faso.
Ateliers du Bocage website (with nice gif pics) is here: http://www.ateliers-du-bocage.com/
There is an article in French about the initiative there: http://www.01net.com/article/317296.html