Thousands of police officers supported by military units will be deployed across France as the country prepares to go to the polls this week to elect its next president.
France has remained on high security alert since a terrorist attack in November 2015 killed 130 people and left hundreds injured. And last year 86 people celebrating Bastille Day were killed when a truck was deliberately driven into the crowd in Nice.
Interior Minister Matthias Fekl announced that 50,000 officers will be mobilised across the 67,000 polling stations, where voters will cast their vote this weekend.
Asked by the Journal du Dimanche newspaper if authorities feared an attack timed to coincide with the election Mr Fekl said: "No threat is being ruled out".
He told the newspaper that the risk of a terrorist attack was "high and permanent" as shown by the attacks last month in London, where five people were killed, and Stockholm, where four people were killed.
The election security plan also includes extra measures to tackle possible violence by extremists groups between the two rounds of the election on April 23 and May 7, Le Monde reports.
French intelligence agency, the General Directorate for Internal Security, has warned the main candidates over "a specific threat on their security and on their campaign headquarters".
This comes only days after an alleged arson attack took place on the Front Nationals' headquarters. Ms Le Pen was quick to accuse "leftists" for carrying out the damage on the building's ground floor.
According to Le Monde, snipers and elite law enforcement units were present during conservative Francois Fillon's rally in Montpellier this weekend.
Emmanuel Macron's team also confirmed that extra security officers had been deployed around his campaign headquarters and that "bomb disposal experts checked the venues ahead of each rally".
Mr Fekl said he was aware of the risk of violent street protest by opponents of the far-right party Front National if Ms Le Pen got through to the second round.
In the face of concerns over hacking and external interference in the election results, Mr Fekl said the software used to send through results for each locality has also been reinforced.