France will take "all measures" to ensure the safety of Sunday's march to be attended by European leaders after this week's attacks and is maintaining its highest possible security level in the Paris area, the interior minister said.
Speaking on Saturday after an emergency meeting with French President Francois Hollande, Bernard Cazeneuve said "we want to keep the high level of mobilisation and vigilance."
"All measures have been taken to assure the security of the rally," he said, after Hollande warned that the threats facing France were not over.
A number of European leaders including German Chancellor Angela Merkel and British Prime Minister David Cameron plan to make an extraordinary show of support for France by joining the mass rally in Paris on Sunday.
The rally comes as the country mourns 17 dead in three blood-soaked days that shook the nation to its core.
Hollande held an emergency meeting of key ministers early Saturday, hours after the dramatic end to twin sieges that resulted in the death of two brothers who had killed 12 at the offices of the Charlie Hebdo weekly on Wednesday.
French forces were hunting for the girlfriend of an Islamist gunman who also died on Friday when security forces stormed a Jewish supermarket in eastern Paris where he had taken terrified shoppers hostage. Hayat Boumeddiene was said to be "armed and dangerous".