Yet the defiant response from across the world has revealed a shared determination to maintain our values in the face of this unspeakable evil.
I was in Paris for Sunday’s Unity March along with millions of people and this message could not have been clearer. What we saw last week was an attack on free speech and the democratic values we hold dear.
It was also an attack specifically on the Jewish community. All of us who are Jews in Britain will feel a particular sense of solidarity with the victims.
The deployment of around 5,000 additional police officers at Jewish schools in France is a sign both of the particular threat the Jewish community faces and the resolve of the French Government to reassure and confront this.
As a parent myself, I understand the anxieties of many French Jews, and the concerns of parents as they take their children to the more than 700 Jewish schools across France.
This attack also comes against the backdrop of growing concerns about antisemitism in France and the UK. More than 7,000 French Jews left the country during 2014 – more than double the figure for 2013 – and last July the Jewish Community Security Trust recorded a record number of antisemitic incidents in the UK.
I have also spoken to people in the Jewish community who, for the first time, feel scared for their children’s future in the UK and are concerned they may be viewed by some as targets. Britain must take these concerns seriously. I believe we need a zero-tolerance approach to antisemitism and to be clear in saying that nothing can excuse antisemitism in any form.
Ensuring there is visible policing and strong community relations must be part of this and we should constantly be asking what more the Government can do to help build confidence in British Jewish communities.
We also need to ensure that antisemitism and racism are tackled online and that sites such as Facebook enforce their own rules when it comes to hate-filled content on its social network.
The shocking online attacks that my colleagues Luciana Berger and Louise Ellman haverecently been subjected to highlight this new danger and there should be no safe haven for antisemites online. That is why Yvette Cooper and I have been calling on social network sites to do more to tackle this insidious threat.
What we saw this weekend in Paris was a demonstration of the defiance and resolve of millions in response to the atrocity of a hate-fuelled few.
With Holocaust Memorial Day approaching on the January 27 in the year of the 70th anniversary of the liberation of Auschwitz and the other death camps, we know that commemoration of past atrocities must be combined with a determination to resist hate and intolerance in our own time.
This is a time to redouble our commitment to preserve the values we hold dearest, and resolve to work together to tackle extremism in all its forms.