I would like to suggest to that person that instead of “praying” for the people of Paris, they instead “care about”, “empathize with”, “stand with”, “mourn for”, “have their heart go out to”, etc. I propose that they should announce that they intend to take action, active or passive, now or in the future, to help make sure that such things never happen again.
When someone says that they are “praying” for France, there are two possibilities: one is that they actually mean “care about”, “empathize with”, and so on. The other possibility is that they truly mean that they are stopping what they are doing and saying words, aloud or to themselves, requesting that a deity take action.
In the first case, the word "pray" is being used as a synonym for "wish." I think it is more valuable, and conveys more substantive meaning, when people speak of their emotional connection with the French and express their grief and anger at the terrible actions that happen last week. I believe that it is a much more forceful statement to say “I feel emotionally connected with you and care about you” than to say “I am praying for you, i.e. I wish that hadn't happened." So, you should stop using the word "pray" and instead unambiguously express your direct human empathy for the suffering of others.
The second case, actually “praying” to a deity in the religious sense, is at best a waste of your time. If you encourage others to literally pray, then you’re actively doing harm. Your prayers, and the prayers of others, will not be answered by the deity that you are beseeching help from. By encouraging others to pray, you are encouraging them to waste their time and offload their opportunity to give tangible assistance onto a mythological being. When you say "I am praying for the people of France," what you are really saying is "I hope that some force (other than myself) will take care of them.” Imagine what could actually be achieved if everyone in the world who is “praying” for Paris actually did something physical, substantive, and material to assist the Parisians, or to actively prevent future heinous acts perpetrated in the name of “god.”
If in your anguish you cry out to the giant teapot circling the sun, asking it to help the people of France, your pleas will not be answered. The giant teapot circling the sun is not listening, and it’s not going to do anything about the terrorist acts in Paris, and most importantly, there is no giant teapot circling the sun! If you think there is a giant teapot circling the sun that you can call to in time of need, then someone should sit down with you over hot cup of tea and explain the nature of reality. If you honestly believe that praying to a deity to help the people of France will actually achieve anything at all, then you really need to take some time and think about reality, actions and actors, that which is measurable and that which is imaginary. If you don’t actually believe in a deity, then you really, really, shouldn’t be praying.
Back to the first case again, if you say that you are “praying” but actually mean that you are demonstrating empathy with the victims of terrorism, then you may inadvertently be causing harm. By using the word “pray”, you are likely to be encouraging others to pray in the religious sense. As described, this is wasteful and harmful. Don’t use the word “pray” if you don’t mean it, and if you do mean it, stop and think about reality – then stop praying, because really you are just wishing, and wishing things were different wont help anyone.
I hope that everyone is pained by the terrorist acts in Paris. I hope that everyone feels positive emotions for those who were hurt, and negative emotions towards those who committed these crimes. I hope that everyone will be driven by those feelings to take actions to help in any way they can, no matter how small. And, I hope that no one will “pray” for Paris.