Newly-released CCTV footage appears to show the partner of Paris supermarket attacker Amedy Coulibaly arriving at an Istanbul airport in Turkey.
The video purports to show Hayat Boumeddiene passing through passport control with another man on 2 January. She is thought to now be in Syria.
French police are seeking her after Coulibaly and two other gunmen launched deadly attacks on Paris last week.
About 10,000 troops have been deployed in France following the attacks.
The violence began after brothers Said and Cherif Kouachi attacked the offices of the satirical magazine Charlie Hebdo on Wednesday, killing 12 people. Witnesses said they shouted “we have avenged the Prophet Muhammad” after the attack.
On Monday, the cover of the latest edition of the magazine, put together by surviving staff, was published in French media.
It depicted the Prophet Muhammad tearfully holding a sign reading “Je suis Charlie” (“I am Charlie”), a phrase used by the magazine’s supporters following the attacks. Above the picture were the words: “Tout est pardonne” (“All is forgiven”).
Charlie Hebdo’s lawyer, Richard Malka, has told French radio that the magazine will “cede nothing” to extremists.
The latest issue, to be released on Wednesday, will have a print run of three million copies, compared with its usual 60,000 a week.
The satirical weekly has regularly courted controversy in the past with its irreverent take on news and current affairs. It was firebombed in November 2011 a day after it carried a caricature of the Prophet Muhammad.