At least 18 people have been arrested after a wave of hoax bomb threats prompted evacuations across France.
The Palace of Versailles, the Louvre, as well as schools, airports and hospitals have all been targeted.
Those behind the disruption are mostly minors, authorities say.
The threats come at a time of heightened tension in France, after a teacher was fatally stabbed by an alleged jihadist last week at a school in the northern city of Arras.
Fifteen regional airports had threats made against them on Friday, from Biarritz, Bordeaux, Nice and Toulouse in the south to Lille and Brest in the north. Airports have been evacuated on several days this week, causing the cancellation of at least 130 flights.
Tourist sites have also been targeted. The Palace of Versailles was closed for the fifth time in a week on Friday after yet another threat, affecting thousands of visitors.
Mayor François de Mazières appealed for the "idiocy" to stop, telling Franceinfo that 10,000-15,000 people visited France's former royal residence every day and warned the hoaxes "could have consequences for attendance".