Some 40 world leaders are expected in Paris ahead of a huge march to show unity after three days of terror that left 17 people dead.
The rally is expected to dwarf Saturday’s marches that saw 700,000 take to the streets.
About 2,000 police officers and 1,350 soldiers are being deployed across Paris to protect marchers.
Police are seeking accomplices of the gunmen who attacked Charlie Hebdo magazine and HyperCacher supermarket.
The interior minister says France will stay on high alert in the coming weeks.
Bernard Cazeneuve will host a meeting on Sunday morning of fellow interior ministers from across Europe to discuss the threat posed by militants.
He promised “exceptional measures” for the massive unity march in Paris on January 11, including positioning snipers on roofs.
The foreign leaders expected to attend the rally include UK PM David Cameron, German Chancellor Angela Merkel, Palestinian leader Mahmoud Abbas and Israeli PM Benjamin Netanyahu.
The march, which will be led by relatives of the victims of last week’s attacks, will leave Place de la Republique at 15:00 local time.
More than a million people are expected to take part.
Before the march, President Francois Hollande will meet leaders from the Jewish community, which is still in shock after a gunman killed four people at the kosher supermarket in eastern Paris on January 9.
The gunman, Amedy Coulibaly, is believed to have shot dead a policewoman the day before.
In a separate attack on January 7, the Kouachi brothers raided the offices of the satirical magazine Charlie Hebdo.
Cherif and Said Kouachi killed 12 people – including eight journalists and two police officers – in the attack. Eleven people were also injured.
Amedy Coulibaly and the Kouachi brothers were shot dead on January 9 after police ended two separate sieges.
Police are still hunting for accomplices of the three gunmen, including Hayat Boumeddiene, Amedy Coulibaly’s partner. However, officials in Turkey believe she may have travelled through the country en route to Syria earlier last week.
Meanwhile, police in Germany say there has been an arson attack at the offices of a newspaper that reprinted Charlie Hebdo cartoons of the Prophet Muhammad.
No-one was hurt in the assault on the Hamburg Morning Post in the early hours of January 11, according to reports.
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