French President Francois Hollande on Tuesday urged the US-led coalition backing the offensive against Islamic State jihadists in Mosul to prepare for the aftermath of the city's fall, including returning fighters.

‘The recapture is not an end in itself. We must already anticipate the consequences of the fall of Mosul,’ he told a meeting of coalition defence chiefs in Paris.

US Defence Secretary Ashton Carter and ministers from 12 other countries attended the talks, which come a week after Iraqi forces backed by Kurdish fighters launched a major operation to retake Iraq's second-biggest city.

‘What is at stake is the political future of the city, the region and Iraq,’ Hollande said, calling for ‘all ethnic and religious groups’ to have a say in the future running of the predominantly Sunni city.

He also appealed for measures to shield civilians trapped in Mosul by the fighting and for ‘vigilance’ faced with the prospect of return foreign jihadists returning home from the Iraqi battlefield.

Of the estimated 4,000-5,000 jihadists fighting in Mosul, around 300 are French, according to French officials.

Hollande reiterated French warnings about IS fighters in Mosul fleeing across the border to Raqa, the group's stronghold in Syria.

‘We must clearly identify them,’ he said.

The French leader also called on the ministers to set out ‘the stages of the next operations’ against IS, namely retaking Raqa.

‘If Mosul falls, Raqa will be Daesh's last bastion,’ he said, using another name for IS, which is also known by the acronyms of ISIS or ISIL.

‘We must see to it that Daesh is destroyed and eradicated everywhere.’