Very sad and I despair at human civilisation most of the time these days. Lots of innocent lives lost for no reason.
Hora (and all)- Don’t let this put you off your plans, routines, etc. There were 150(ish) killed in this attack, in a city with a population of over 2.25 million. What is the true probability that it would have been you if you were in Paris. Same goes for London (or any other large city). In reality the probability of you getting targeted or even being near the attack is miniscule.
The terrorist want you to be scared. That’s the point. Just carry on as usual and don’t play into their hands.