Locating person in France isnt too easy for English-speaking people - first of all you must know a little french. By the way, you can use any online translation service to use french people finders as well, as the native.
PagesJaunes is official white pages of France, including the French overseas territories and departments. You can search by names of people, but in french only. Reverse search (search by number) is very useful feature.
AskAlix is good nationwide business directory for France. Its more than a search engine, its the unique combination of a business directory comprising millions of information on French companies and a powerful search engine based on the accuracy and reliability of the results.