If you are looking for French titles to supplement your Immersion collection, and you are working in an "hors-Québec" Canadian school, you will often find that local booksellers have a very limited French selection. Chapters carries just a few books, and Amazon.fr prompts me to order titles from Europe. If I choose the French version of Amazon.ca, the titles I see are still mostly English.
My solution? I click on the website of Renaud-Bray . This well designed bookstore has suggestions for novels, movies, music and best of all, it's Canadian (good for me, as I am in Canada!) Order enough, and shipping is free. Great selection, and no-fuss shopping. One of my strategies is to select teen novels that have been translated from English. The students are always keen to read something from a series or an author they know.