"The threat is strong, our response has never been stronger," Interior Minister Bruno Le Roux said on Friday.
While France is in the throes of an unprecedented jihadist threat since the attacks of January 2015, and 17 bombing projects have been thwarted on national soil in 2016, the security measures have been "adapted every time" "Said, Mr. Le Roux.
This is all the more so after the attack on a Christmas market in Berlin Monday, claimed by the Islamic state, which left 12 dead and dozens wounded, and whose alleged perpetrator, Anis Amri, was killed By the Italian police on the night of Thursday to Friday in the suburbs of Milan.
The "risk" of an attack on the day of the celebration by Christians of the birth of Jesus - which would have a strong symbolism for the jihadists - exists, although there are "no formal elements" about a threat, Said Jean-Marc Falcone, Director-General of the National Police (DGPN), in an interview with the Journal du Dimanche published on Saturday.
In addition to the 91,000 members of the security forces deployed on Saturday and Sunday in the territory, SNCF armed agents are now present on the trains, said the president of the SNCF Guillaume Pepy on Friday.
About 2,400 places of worship will be monitored on Saturday evening, detailed Bruno Le Roux, which seeks to "reassure" the believers on their "security".
In Paris, a few hours before midnight Mass, in front of Notre-Dame Cathedral the esplanade was surrounded by metal barriers. Many policemen search the bags of people wanting to access the building, ask to open the coats, said an AFP journalist.
At the top of the Montmartre hill, at the entrance of the Basilica of the Sacred Heart, another religious monument emblematic of Paris, a guard inspects the bags with a small torch. In this very tourist area, five police vans park on one side and five on the bottom of the building.
A young Argentinian couple, traveling to Paris for four days, takes a picture in front of the basilica and the panorama. Elsa says she is "moderately reassured" by the police presence, but she "is not afraid".
In the cathedral of Strasbourg, the office will also obey strict security measures: checks, bag searches, access and limited places.
"For the most frequented Christmas masses, identified in some large cities, we will not only have a police presence but a quasi-immediate response capacity," assures the DGPN.
An effort welcomed "very willingly" by Monsignor Dominique Lebrun, archbishop of Rouen because it will calm "the anxiety" of some faithful.
However, it is "impossible to protect all the churches", he remarked on RTL's microphone, citing the example of Saint-Etienne-du-Rouvray, in which a priest was assassinated at the end of July by two jihadists Claiming the EI.
The head of the national police also explains that safe "reassessments" were made locally.
Thus in Lille, where 1,250 troops are mobilized, "an unprecedented device" has been put in place, according to the prefect. One-tonne concrete blocks were laid in strategic locations in the downtown area as well as in the vicinity of the huge Euralille shopping center.
The same "anti-vehicle" blocks are used in Marseille, in addition to barriers, metal studs and a strong police and military presence, to protect the Christmas market, located on the emblematic Old Port.
"Fear, of course, it's scary, but we do with it," admits Massimo Esposito, an Italian tourist. "It's the same in England, it does not really change us," says Key Saunders, a British cruise on the Mediterranean.
The Minister of the Interior urged the French to "exercise vigilance and serenity". "We can go out, party, go to friends, go to religious services, I invite everyone to live freely".