A French Muslim convert was seen in a line-up of Islamist militants with Isis (Islamic State) before the beheading of a US hostage and 16 Syrian prisoners in November. And before Christmas, a series of apparently unrelated attacks by "lone wolf" Muslim extremists jangled nerves across the country.
One attacker in the central town of Dijon left 13 people injured after driving his car into groups of pedestrians, while another near the western town of Tours tried to stab a police officer to death before being killed by police. A third rammed his car into shoppers at a Christmas market in Nantes, before stabbing himself.
Following the worst terrorist attack on French soil in decades, it could be difficult for the authorities to keep the lid on the kind of anti-Islamic rhetoric which has been espoused by the National Front, and which may lead to a violent backlash. Germany is facing similar problems, with increasingly large anti-Islam demonstrations.
French police said they were astonished by the huge numbers who turned out spontaneously to express solidarity peacefully with Charlie Hebdo in the name of freedom of expression. Thousands converged on the Place de la Republique in Paris, near the magazine's offices, while many thousands of others gathered in towns and cities. They did not carry anti-Islamic slogans.
The attack must still be the Government's worst nightmare. Anti-terror investigators have warned that the greatest risk is from returnees who have travelled to Syria to be indoctrinated into jihad and then come home.
The challenge for the Government will be to try to prevent a rise of Islamophobia from leading to an increase in terrorist attacks, and that will not be easy. Turkish Foreign Minister Mevlut Cavusoglu pointed out that the two feed on each other. "We need to battle both Islamophobia and terrorism."