As well as military and security measures, stepped up since the 2015 Paris terror attacks, the authorities must "tackle the struggle for influence on social media, fight the war on the terrain of ideas", Valls told a press conference on Friday morning.
The latest publicity campaign, which aims to combat "propaganda that takes the form of a musty neoromanticism" according to Valls, consists of two videos filmed from the point of view of a boy and a girl tempted by radicalisation.
They are interactive, allowing participants to choose between listening to friends and acquaintances or jihadist recruiters, and end with the girl in a forced marriage in Syria and the boy carrying out a terror attack in France.
"You are responsible for your choices," the site tells viewers adding the message, "radicalisation can destroy your family, your life and those of others".
The videos will be posted on a new website, toujourslechoix.fr, that will complement the already existing stop-djihadisme.gouv.fr, and will be publicised on TV, radio and social media.
The authorities have blocked 367 websites because of their alleged links to terror networks, Valls said.
Recruitment to armed groups reduced
Officials recorded 18 people going from France to Syria and Iraq in the first half of 2016, compared to 69 in the same period of 2015, and 12 people returning, compared to 25.
"We have a very clear phenomenon of a reduction in departures since the beginning of 2016," Interior Minister Bernard Cazeneuve said.
He said the fall was the result of government bans on suspect individuals leaving the country, the evolution of the conflict, which has seen the tide turn against the Islamic State armed group, and improved collaboration with Turkey, the point of transit for most would-be fighters.
Nearly 400 people have been arrested on suspicion of involvement in jihadist activities since the beginning of the year, according to official figures.
There have been almost 12,000 tip-offs of radicalisation, 5,700 through the hotline set up by the government.
Three terror suspects released
Three men were released on Friday after being detained on Tuesday, suspected of providing logistical support to Sid Ahmed Ghlam, the Algerian student accused of killing a young woman and plotting an attack on a church in 2015.
A fourth man, who was also detained on Tuesday, was still being questioned.
His DNA is reported to have been found on the body armour found when Ghlam was arrested and investigators have the right to hold him until Saturday without charge.
Council takes legal action against baby's name
The local council of Nice, the Riviera town where 86 people were killed by a man driving a lorry into a crowd on Bastille Day, has filed a complaint over the naming of a baby after terror attacker Mohammed Merah.
The case argues that being called Nizar Merah Mohamed could be against the child's interests, the only reason for which the use of a name can be forbidden.
High-profile local poltician Christian Estrosi called the name "inadmissable" and slammed a "birth certificate whose content is an attack on the republic".
Merah killed seven people in the south-western towns of Montauban and Toulouse in 2012.