The Islamic State group, or ISIS, claimed responsibility in the hours after the explosions, but it took almost no time for those watching to begin speculating about who was responsible for the attacks and how to prevent them in the future.
Republican presidential frontrunner Donald Trump took the opportunity to once again propose closing the United States' borders.
But as the world searches for answers in light of yet another horrific act of extremist violence, Muslims are bracing themselves for yet another round of Islamophobia.
It's already started on Twitter:
And once again people have been forced to come to the defense of Muslims across the globe. Islamophobia has never successfully prevented an act of terror. It's only worked to target, humiliate and alienate people who happen to be brown and may, in fact, be Muslim.
As details of this vicious attack trickle in, it's important to remember that terrorist violence is born out of intolerance. The worst way to defeat hatred is with more hatred — and only plays into the hands of terrorists.
Juan Cole, a scholar who focuses on the Middle East at the University of Michigan, wrote after the Charlie Hebdo attacks in Paris that resorting to hate and Islamophobia in the aftermath of an attack like today's simply plays right into extremists' strategies. It's a strategy that's long had a name: "sharpening the contradictions." Cole describes this as "a strategy is the strategy of sociopaths and totalitarians, aimed at unmooring people from their ordinary insouciance and preying on them, mobilizing their energies and wealth for the perverted purposes of a self-styled great leader."
The only thing that terrorists want to do more than create fear and paranoia is to provoke hate, which only serves to galvanize their sympathizers and lead others to vilify millions of people. It's at times like these when we can't allow that to happen.
March 23, 2016, 11:05 a.m.: This story has been updated.