At the beginning of the month Arthur Keefer posted "Could Charlie Hebdo have been prevented if France allowed religious instruction? (COMMENTARY)" on the Religious News Service's website. Though I do not oppose "religious instruction" outright I do find the idea to be very problematic. Keefer seems to be blissfully ignorant of one of the biggest problems with allowing religious instruction in public institutions. The term is rather amorphous and open to interpretation. Not everyone means the same thing when they talk about "religious instruction".
If Keefer means that a general overview of multiple faiths in terms of the most commonly accepted tenets within each and how each faith has influenced and been influenced by local, regional, and global culture, I would support such an idea. However, that still doesn't mean it would have prevented the tragedy that occurred at Charlie Hebdo. Comparative religious studies can increase tolerance in the general population that participates in such studies but it is not a panacea. Various studies have indicated that a percentage of the population will not only fail to become more tolerant but will in fact become more extreme if that is the mind-set they have already embraced. Religious instruction is just one potential mitigating factor. By itself it cannot accomplish nearly as much as Keefer seems to think
Ultimately, there is just as much reason to believe that relatively strict secularization is just as effective in terms of containing and combating religious extremism as is inserting religious instruction into public education. Personally, I think we should be teaching comparative religion in public education but do not assume it will automatically quell religious extremism. I would encourage it more out of a deep seated loathing of ignorance. So long as religion is a major component of culture it should be taught in as objective a manner as possible. This, inevitably, leads to another problem Keefer overlooks and a major reason why religious conservatives will continue to oppose religious instruction over religious indoctrination. Studies have shown that the more exposure to comparative religion a given population receives the lower the rates of religiosity (in terms of organized religious observance) among that same population.
So, no, it is highly unlikely that religious instruction would have made a difference in France when it comes to the most extreme among the religious right.