Positive lightning?
Airfrance is a western airline with a reasonably good reputation for maintenance (even if their customer service is debatable). The plane type involved is reasonably modern and we would assume that the pilots would be looking to minimise turbulence by trying to avoid the cb cells. As other posters have noted, normally lightning strikes are of discomfort but no major concern.
There is a rarer (<5%) but documented phenomenon known as positive lightning which can come from the top of the 'anvil' to the ground some distance away from the storm. These have between 10-100 times the power of normal strikes and have been implicated in some crashes including Pan Am 214 in 1963 and the in-air breakup of a glider in 1999. Even the most modern planes would have a serious problem with such a strike.
Anyway hoping nothing of the kind happened and that somehow the plane managed to ditch.