There is something fundamentally rotten at the heart of the European far-left. In Britain it manifests itself in institutional anti-Semitism, whereas in France the loathing is aimed at the police.
On Saturday, hours after Arnaud Beltrame lost his fight for life following his heroic gesture during the Islamist attack in Trebes, a gentleman called Stéphane Poussier tweeted his pleasure at the news of the police officer's passing. Poussier isn't just any old troll eaten up with hate; last year he stood as a candidate for the far-left's La France Insoumise party in the parliamentary elections.
Jean-Luc Mélenchon, the leader of France Insoumise, moved swiftly to distance himself and the party from Poussier's remarks, condemning them unequivocally, but the damage has been done.
For many in France, Poussier's remarks will reinforce their view that a minority of the far-Left detest their country so much they would take a perverse pleasure in seeing it overrun by Islamists.
Hatred of the police has a long history in France (a "French speciality", according to sociologists) but in recent years the violence against the forces of law and order has increased and intensified. Last October, seven members of Antifa were convicted for their part in firebombing a police car in central Paris during an anti-government demonstration in 2016, and then assaulting the occupants as they tried to escape their burning vehicle.
The conviction of the group drew a swift response from their far-left comrades. First an arson attack was launched against a police barracks in Limoges and a few days later a Grenoble barracks was fire-bombed, resulting in the destruction of a dozen vehicles.
During last Thursday's day of strikes against the government reforms, Antifa militants ran amok in Rennes, Nantes and Paris, smashing shop windows, torching cars and attacking the police, several of whom were injured.
In the short term the violence, combined with the comments of Stéphane Poussier, are likely to further weaken support for the far-left unions as they seek to step up the strike action. Last week's strike, the first in what the unions hope will be a spring of discontent, didn't cause the disruption the unions had hoped, further evidence that their ability to mobilise the masses is weakening. That, in part, is because the French, while they may find some of President Macron 's reforms unpalatable, nevertheless recognise that they are necessary to modernise the economy. But also it's because men and women who might in the past have peacefully demonstrated their opposition to economic reforms have been frightened off the streets by the thuggish fringe of the far-left, these boys in black who call themselves anti-fascists but dress and behave like fascists from the 1930s.
Worryingly for the government, the far-left thugs have not only frighted the moderate left off the streets but they appear to be rousing their counterparts on the right, raising the spectre of a slide towards civil war that for years has haunted the French.
Two years ago Patrick Calvar, head of the DGSI, France’s internal security agency, warned a parliamentary inquiry that the country "was on the brink of a civil war" because of rising tensions between the far-left and far-right, with the latter regarding attacks on the police as treasonable at a time when security forces were also being targeted by Isis. This has always been the Islamists' strategy, to set the French against each other, to "fracture" the country.
And fractures are beginning to appear. Among the protestors last week were a group of students who embarked on a peaceful 24-hour sit-in at the law faculty in Montpellier University. Late on Thursday evening a dozen masked hooligans, described by the French press as belonging to a "Fascist Milice", burst into the auditorium and beat up the students. That led to a march through Montpellier on Sunday, and a confrontation between 200 far-left militants and around 30 members of a far-right organisation called Ligue du Midi.
It could be a sign of things to come in France as the far-left and far-right start to square up more often, leaving the Islamists looking on gleefully from the sidelines as their strategy comes to fruition.