The broadcast of carefully staged videos of beheadings is a weapon used by ISIS to terrorize Western countries.

But it's the first time this gruesome act has been perpetrated on French soil, claiming the life of the ordinary manager of a delivery company. The man's head was hung up on the fence of the Air Products chemical factory in Saint-Quentin-Fallavier, near Lyon, with words in Arabic written on it, framed by black flags. The suspect has been identified as Yassin Salhi, a 35 year-old father of three who was listed for radicalism a few years ago, but was never prosecuted. He worked in the same company as the victim, and was described by his neighbours as a discreet family man. He used his van to drive into gas canisters, only causing a minor explosion, and was arrested by the police, along with his wife and his sister.

Friday's events, as well as the bloody attack against foreign tourists in Tunisia, is a reminder that terrorism can strike anytime, anywhere. The French are well aware. After the killings at Charlie Hebdo, Montrouge and a kosher supermarket in January, a would-be Jihadist, Sid Ahmed Ghlam, plotted an attack against a Catholic church. A young woman, Aurélie Châtelain, was the innocent victim of his failed attempt in April. A sense of horror and powerlessness has spread among the public , with some irrational consequences.

Only last week, with the beginning of Ramadan, the foodie website Marmiton published a selection of recipes for the event, with the words 'Happy ramadan to all'. It was inundated with outraged comments such as 'We don't care about ramadan, we are in France' or 'You are betraying French culinary tradition'. The community manager of the website calmly answered that the same applied for Christmas, Easter or Hanukka and that 'good food brings peace in the world'. Around the same time there was the story of a school party in a Corsican village where teachers asked children to sing John Lennon's song Imagine in five langages, including Arabic. Some parents protested, others threatened to disrupt the party, and it was cancelled. These are just two incidents - but it shows the level of hysteria surrounding anything related to Islam here.

Then again, the French love controversy. On the other end of the political spectrum, a well known demographer and historian, Emmanuel Todd, claimed in his book 'Qui est Charlie?' (Who is Charlie?) that the massive demonstration that followed the killings of Charlie Hebdo on January 11 was 'a scam', contrary to mainstream opinion that saw it as a show of unity and fraternity. 'When four million people gather to say that it's an absolute right and even a duty to caricature others' religion, and when these others are the weakest in society, one is perfectly free to think they are right and good and live in a great country. But it's not the case'', he said to French news magazine L'Obs. Commentators objected that Todd, who was not in the crowd on January 11, misjudged the motives of the respectful demonstrators. Sophia Aram, a humorist of Arabic origins, pointed out the patronizing tone of the author who deemed all Muslims 'weak'. But six months on, the truth is that France is not united. It is divided. Even inside Charlie Hebdo, 'l'esprit du 11 janvier', the spirit of January 11, is hardly living on. The paper is overwhelmed by the amount of cash it received after the attacks and its traumatized staff are tearing each other apart. There is also the issue of refugees, from Syria and possibly from Tunisia, who will inevitably leave the country with the collapse of the tourist industry. In a country plagued by 10 % unemployment, this is not a good time to show solidarity.

Since Friday, the reaction of the government has been to call a select committee with French president François Hollande, Prime minister Manuel Valls and the main secretaries of state. The country is already on red alert and armed forces are working around the clock to protect sensitive buildings. François Hollande and his Home Secretary Bernard Cazeneuve are reknowned for their cool and composure but calls for a harder line are being heard. 'Pas d'amalgame' (no confusion between Islam and terrorism), the mantra of the last few months, is more and more dismissed as too soft and ineffective against the brutality of the enemy. This is best summed up by Saturday's column in Le Figaro, the prominent right-wing daily. Under the headline 'The debate that can not be pushed aside', political editor Guillaume Tabard calls for a national debate on Islam, that can't be left to the far right party National Front.

We face the same dilemma all over again: because of a handful of extremists, should millions of French Muslims be suspected? Should non-Muslims feel threatened by hallal butcher shops, by women wearing the islamic veil, by a peace song in Arabic? In the run up to the next presidential election in 2017, Nicolas Sarkozy is already playing that card, to lure Marine Le Pen's National Front electors. This week, the parliament passed a bill to increase the power of the intelligence service. The government swore it was not a French Patriot Act. No doubt a lot of people wished that it was.