More than three million people have taken part in unity marches across France after 17 people died during three days of deadly attacks in Paris.

Up to 1.6m are estimated to have taken to the streets of the French capital.

More than 40 world leaders joined the start of the Paris march, linking arms in an act of solidarity.

The marchers wanted to demonstrate unity after the attacks on satirical magazine Charlie Hebdo, police officers, and a kosher supermarket.

Gavin Hewitt reports from Paris.