Authorities say 26-year-old Hayat Boumeddiene, the girlfriend of Amedy Coulibaly, who died on Friday when security forces stormed a kosher supermarket in eastern Paris where he held shoppers hostage, is "armed and dangerous."
Police say Coulibaly shot dead four hostages before authorities killed him in a shootout.
As law enforcement officials frantically searched for the woman, French President Francois Hollande held an emergency security meeting of key ministers Saturday.
Following the Elysee Palace meeting, Interior Minister Bernard Cazeneuve said the government would deploy hundreds of troops in addition to thousands of police officers and other security forces already on the ground. He added France would maintain its terror alert system at the highest level throughout Paris.
Special security provisions will be implemented for a march on Sunday, at which various heads of state, including German Chancellor Angela Merkel, British Prime Minister David Cameron and Spanish Prime Minister Mariano Rajoy, are expected to attend.
"I call all French people to rise this Sunday, together, to carry these values of democracy, liberty, pluralism, to which we are all attached,Hollande said.
Following warnings by Hollande that terrorist threats in the country "weren't over", the Yeman-based al-Qaeda in the Arabian Peninsula (AQAP) Islamist group issued warnings of fresh attacks against France, accusing it of targetting Muslims.
"You, French people, have to stop your aggression against Muslims in order to live safely. If you want war, then by Allah you will not enjoy security," AQAP cleric Harith al-Nadhari said.
Al-Nadhari praised the assailants who carried out the attacks in France on Friday, saying in a message broadcast online, they were "soldiers who do not fear death."
Satirical weekly newspaper Charlie Hebdo, where 12 employees were killed on Wednesday by Islamist extremists, was known for printing cartoons of the Islamic prophet Muhammad, as well as other religious figures.
AQAP is said to be one of the international terrorist network's most dangerous branches.
jlw/gb (dpa, AFP)