It's pretty obvious that an attack in France will create more media attention from us, as France are a neighbouring country to us. So we as a nation are obviously going to be more concerned when these attacks are happening near our doorsteps, than if the attacks are happening in Syria.
France are also an allie of ours, where as Syria are not. So an attack on France has the potential to trigger our armed forces into action.
I partly agree with you.
I don't agree that people watching the news last night, were generally thinking "oh my god, this could mean our military gets involved",
I think they were generally (quite reasonably and understandably) feeling the horror of the situation and feeling deepest empathy for those who got caught up in it.
To a degree, they could also have been thinking 'Christ, it could be us next'.
And whilst the 'Christ it could be us next' factor is certainly more relevant when it happens in France, than when it happens in Syria, and is therefore a reason why it has a bigger emotional effect on us than when 200 Syrians are executed in cold blood in Syria, I also suggest that the fact that it was French people who were killed, rather than Syrian people, makes it a far bigger story, and in our eyes a bigger tragedy.
On this basis, I would suggest that if the 200 French had been killed by ISIS in Syria, rather than in France, it would still have affected peoples' sensibilities here more, than if it had just been another 200 Syrian people murdered by ISIS in Syria.
In western eyes, Syrian lives are worth less than French lives.