When Charlie Hebdo cartoonist Coco thought back and drew for a new documentary about the slaughter she survived 10 years ago at the French satirical journal, the memories that streamed from her marker pen were all black.

France on Tuesday commemorated the victims of the deadly assault on the Charlie Hebdo satirical magazine 10 years ago that began a spate of Islamist militant attacks on the country and stoked a debate on press freedoms that still rages today.

Terror attack on French satirical magazine united the Western world in defence of free speech, but a decade on some claim 'the killers have won'