...Count me out of the mass signs of unity, the 'our thoughts and prayers are with you', etc routine.
In fact, I regard this 'All of the world stands with you now, France!' schtick to be part of the problem. Whatever problem ISIS poses to the western world, nations have responsibilities to their own people first and foremost. France should defend itself, Paris should look after Parisians, and the people whose homes are in Paris (not 'who live there', but whose home is there) have the first responsibility to look after their home.
It is not France's primary responsibility to look after Syria. The belief that it is their responsibility is part of the reason they have this mess on their hands to begin with.