I can counter your statement of why didn't gun control laws keep france safe with why have Australia's gun control laws worked
Because its only a matter of time before some crazy jihadist pull this crap in canada, UK, australia, etc. They already have in smaller ways, now the Paris incident is going to be copied. Gun laws are like traffic laws, they work for those who obey them. One might even say killing someone with your gun in a rampage shooting is breaking a gun law. Once you become an outlaw, all the politics in the world don't matter.
as long as their are customers there will be suppliers. legal or illegal