The current state of high alert has been in place since 2015, after 130 were killed in Paris.
The winner faces a tough fight.
Sanctions tell U.S. allies that America understands and condemns Russian action.
Leading contender Manuel Valls, the former prime minister, is seen as not likely to prevent a runoff between conservative Francois Fillon and far-right Marine Le Pen.
Hollande's decision leaves an opening for a Socialist to challenge Marine Le Pen and Francois Fillon.
"People on the left are in despair at the situation," Alexis Bachelay, a left-wing Socialist MP, said.
Unpopular president is forecasted to lose a three-way race between Marine Le Pen and the winner of the Les Republicains' primary.
With favorables lower than the alcohol in a bottle of Bordeaux, President Hollande is in serious trouble.
A runoff is expected between Francois Fillon and Alain Juppe for the right to face the National Front's Marine Le Pen in the presidential election in 2017.
Alain Juppe is the favorite, with former president Nicolas Sarkozy and Francois Fillon also vying to face National Front leader Marine Le Pen.
Russian attacks on Syrian civilians have undercut efforts to ease Donbass-related sanctions.
A new poll finds that more than half of French people worry schools are not safe enough.
Montebourg is an anti-austerity firebrand who served under Hollande but resigned in 2014.
Matteo Renzi will host Angela Merkel and Francois Hollande to discuss reverberations from Brexit vote.
The Kremlin has consistently used acts of terrorism as pretexts for the state of emergency Russia has been living under throughout the Putin years.
Due to France's security situation, ministers will have to remain in Paris.
A French counter-extremism court formally charged two Albanians and three Tunisians on Thursday.
The truck attack involved five further suspects who are in custody, Paris prosecutor said.
Fatima Charrihi, 62, was on the Promenade des Anglais with her family last Thursday.
An old friend says the delivery driver may have been scarred by a turbulent relationship with his father.
French authorities made the discovery on Bouhlel's phone after his truck attack on Thursday.
Extremism has taken a hold in the French Riviera city, leaving its Jewish community on edge.