French Newspapers I love this free app - it's the best French newspapers (20 Minutes, Le Monde, Le Figaro, and more). A great way to keep up with French news if you are French, a great way to learn and practice your French reading if you are not.
Google Translate Though this isn't the best French translation app - it's free and it works for a huge list of languages and because it's a Google app it is updated all the time. Google used their free Goog-411 service to collect a gigantic library of spoken words in all languages - which is what powers this app.
Littre French dictionary This is a small, free, easy to use French dictionary that focuses on classic and literary French from the 17th and 18th century. Good for students of French lit.
French Verbs This free app is small, works offline, and has no ads. It is a basic reference for French verbs and their conjugation. The only downside is the pronunciations, which are digitally produced and therefore often incorrect - but it works great as a written reference.
Oxford French Dictionary As far as I'm concerned the Oxford is the best dictionary app for any language. This French dictionary has over 555,000 translations and costs US$24.99. You can d/l the whole dictionary so that it will work offline.