I’m surprised nobody has mentioned the terrible loss of life when the Russian airliner...
Yes, with twice as many dead. Earlier this year, the same religious ideology was behind a university attack with more dead students than in Paris. Mass casualties by suicide bombers (or otherwise) in Lebanon and Iraq too.
It is hard and risky to wade into reasons why we react differently to similar tragedies, but if I'd venture a guess, I'd say we get desensitized over time for repeating tragedies. Airplane bombs are nothing new, and as horrible as it might sound, mass tragedies are just another Monday afternoon in Africa and the Middle East. Not to mention it is away from us, and it is "them," not "us" (again, as horrible as it sounds). Paris, however, is "us," not only civilization-wise, but also because "we" could have been there, it is "our" Paris, most of us visited at some point in our lives or have it on our bucket list at least.