Visitors to France may be surprised to find soldiers armed with assault rifles patrolling airports, railway stations and streets.
But the French have got used to it - they've had 20 years to do so, even though Vigipirate was supposed to be a package of "exceptional" measures when it was brought into force.
Based on legislation passed in 1959 during the Algerian war of independence, it was first introduced during the first Gulf War in 1991, suspended and then brought back into force on 8 September 1995, the day after a carbomb went off outside a Jewish school in the central city of Lyon.
It has only been suspended once - for two months in 1996 - and is now described as "permanent" in official documents.
Some 7,000 soldiers and 30,000 police and gendarmes are deployed at 5,000 sites judged to be at risk.
It's not clear how effective the measures are.
Experts say it may have discouraged individuals from launching attacks, but there's no way of judging how many.
But they say that organised groups are usually determined enough to find a way round the measures.
Nevertheless, it looks as if Vigipirate is here to stay.
"No politician is going to end it for fear that there's an attack the next day and he is blamed," Patrice Ribeiro of the police trade union Synergie-Officiers told Le Monde newspaper.
Another police officer, Jean-Hugues Matelly, described it as "more a political than a security tool".