Michel Onfray tweeted his controversial reaction the day after the atrocities telling followers: "Right and left sowed war against political Islam, and now they are reaping it back."
Widely seen as a maverick among left-wing thinkers, Onfray has long argued that the West should get out of the Arab-Islamic world and let the people there sort out their own problems.
Though in general he is scornful of Islam, his pronouncements have periodically received the dubious endorsement of so-called Islamic State (IS). His tweet even appeared on an IS propaganda video.
According to a French member of IS (speaking of Onfray and quoted by the expert in jihadism David Thomson), "we accept the word of truth, even from the mouth of the worst of the miscreants.