Plenty of reasons that there is a difference in reaction.
1. Familiarity. Lots of people have been to Paris, not so many to Moscow.
2. Culture. France is an enlightened democracy with plenty of shared values. Russia is a totalitarian state run by a corrupt despot.
3. Coverage. Paris, as the capital of a democratic country, has a lot of news broadcasters and the amount of footage and reporting was enormous. Moscow is a totalitarian state with few foreign news teams (and limited in what they can do or where they can go). And the state run propaganda chanels are generally crap.
4. A lot of the pro-Paris stuff was from within Europe, whose nations are VERY closely tied to one another these days. Except for Putin's Russia and its satellite states, of course.
5. Unlikely to go to war any time in the next century vs Putin says in his statements that he should be ruling at least half of Europe and have troops in Berlin.
So, yeah, there are major differences as to the reaction. With the Russian attack there is empathy for the victims but not the widespread outpouring of support as there was for Paris. It also does not help with the sympathy angele that Putin is blaming the west/Ukraine for the IS attack, which is complete bollocks.