US Secretary of State John Kerry has apologised to the French government for not attending a unity march in Paris last week, in the wake of the Islamist attacks that left 17 people dead.

France's Foreign Minister Laurent Fabius said Kerry expressed his regret for the failed appearance as the two met in Paris on 16 January.

"He told me not being able to be there had hurt him," Fabius said, Le Figaro reported. "[He] apologised."

The Obama administration was heavily criticised for having sent only the US ambassador to France and not a higher-profile figure at the rally.

The demonstration was attended by numerous heads of state, including Israeli Prime Minister Benjamin Netanyahu, Palestinian President Mahmoud Abbas, British Prime Minister David Cameron and German Chancellor Angela Merkel.

Kerry said he was unable to join the march as he was travelling from India to Bulgaria, Fabius said.

In Paris, the secretary of state also met with French President Francois Hollande and paid his respects to the victims of last week's shootings.

"I think you know that you have the full and heartfelt condolences of the American people and I know you know that we share the pain and the horror of everything that you went through," he told Hollande. "Our hearts are with you."

He tweeted:

Brothers Said and Cherif Kouachi killed 12 people at the offices of satirical magazine Charlie Hebdo before taking a man hostage at a printing warehouse in Dammartin-en-Goële.

Meanwhile, gunman, Amedy Coulibaly shot a policewoman dead and then stormed a kosher supermarket killing four Jewish shoppers.

All three attackers were killed by police at the end of two separate tense hostage stand-offs.