Flight has more info from the interview of AF CEO Pierre-Henri Gourgeon, which is much more interesting that than the bits that have been cited here earlier.
Notably:
[AF559] crossed a turbulent area that had not been detected on weather radar and, as a result, increased the sensitivity - subsequently avoiding a "much worse" area of turbulence. ... The crew initially chose to deviate 20nm to the west but the radar then showed an extensive squall line which led them to deviate to the east by 70-80nm.
See
Air France reviewing weather-radar use after AF447 crash: CEO