A picture of raw fury and utter despair, she has not merely gone viral. She has now had her face transposed online on to the Mona Lisa, Les Miserables, Joan of Arc and every other iconic image of France, her shock emblematic of an entire traumatised nation.

She is the unnamed woman filmed trying to prevent a masked mob from ransacking a Paris supermarket this weekend. 'Arretez!' ('Stop') she cries repeatedly in vain. 'C'est pas la cause!' ('It's not the cause').

The mob push her aside contemptuously. 'It's feeding time!' shouts one. 'Grab all the wine!' shouts another, while a terrified member of staff looks on, every bit as impotent as the French state has proved to be in recent days.

Standing outside the very same shop yesterday – a branch of the popular Franprix chain on the Rue du Faubourg du Temple – I find that the sense of shock has not subsided.

Local pensioner Annie Tyger arrives, clutching a couple of shopping bags, and finds boards across the windows. Sheets of cracked, reinforced glass lie in heaps on the pavement. A security guard explains that there will be no shopping today (or for the rest of the week for that matter).

Annie promptly bursts into tears. 'C'est des crapules!' ('They're scum!') she sobs. The shop manager, Kine, emerges to comfort her.

I ask if she knows the gallant woman who confronted the mob at the weekend. 'I don't know her name. She just comes here now and then,' Kine tells me. 'It was a scary moment. She was courageous.'

It certainly takes guts to stand up to a gang of masked thugs and tell them that violence is not helping their cause. But what, precisely, is that cause?

That is a question France now, disturbingly, finds itself unable to answer. This is a country with pitchforks in its DNA. The French regard protesting much as the English view cricket.

When French farmers or fishermen or pensioners or anyone else feels hard done by, they take their grievance on to the streets.

It usually does the trick, which is why their economy is a Ponzi scheme of unaffordable subsidies and everyone retires on a fat state pension at 62. Even Britain looks productive in comparison.

All this muscular civil disobedience is why France has no less than four divisions of full-time riot police (the famously no-nonsense CRS, the 'mobile' division of the Gendarmerie, the BRAV-M motorised rapid-response force and a more recent creation called the 'C.I'. or 'intervention companies').

They amount to more than 26,000 full-time paramilitary anti-riot personnel (in Britain we have none) who routinely deploy with an array of semi-lethal weaponry and water cannon.

Yet they proved woefully unable to contain the looting and wanton destruction which broke out across France over the weekend – a new low, even by France's Olympian standards of rioting.

The full damage has yet to be added up but the tally of arrests has already surpassed 2,000.

And, two days later, the aggro is still simmering with more of the same to come. Traditionally, a day's rioting is followed by relative calm. Yet I arrive in Paris on the afternoon following Saturday's mayhem and the running battles are still going on.

Even in the early hours of yesterday morning, I find vanloads of CRS cops chasing masked gangs down one of the smartest streets in all of France, the Rue de Rivoli. 

Much of it seems like a game. The police cannot match the speed of the runaways but are in jovial mood when I chat to one unit. One jokingly waves his shield which has a sticker saying 'ACAB' on it. This is an old English criminal acronym – 'All Cops Are Bastards' – yet it is a universal slogan, much beloved of rioters here in France.

It has been sprayed on walls and statues all over Paris this weekend. Yet here is a riot cop wearing it as a badge of honour.

There is still sporadic looting going on. I walk past an optician's showroom by Rambuteau Metro station which has just been raided. Branded glasses and sunglasses are prime targets, it transpires, as they are light and easily sold on.

Further on, the police chase another hooded gang into a Metro entrance at Les Halles, the largest station on the network.

Rather than pursue them into this warren, one policeman simply lobs a tear-gas grenade down the stairs after them, and a cloud of smoke wafts back up.

There is considerable confusion between the various branches of the police. One lot wave you down a particular street; moments later another lot tell you to go the other way.

Come daylight, the situation is no clearer. Part of the reason that police control broke down over the weekend is that no one can agree on who is protesting about what. 

Big student protests have been happening for several weeks, ostensibly because of poor school facilities. The students were out again all over France on Saturday, joined by the massed ranks of 'France Unbowed', the far-Left disciples of Jeremy Corbyn soundalike, Jean-Luc Melenchon, who is gearing up for next year's presidential election.

Both groups share a number of grievances, not least the 'cost-of-living crisis' and Gaza. The same day saw a resurgence of the Gilets Jaunes movement, a working-class uprising against fuel prices and 'austerity' which repeatedly brought France to a standstill between 2018 and 2020.

Now it appears to have reawoken over diesel price hikes. Lumped together, all of the above amounted to what commentators have called 'a perfect storm' of protest this weekend.

And while Saturday's initial marches proved to be peaceful, more sinister elements were waiting to take things further.

Starting with the occasional projectile hurled at the cops, these encounters inevitably escalated into running battles all over France.

The police used baton charges and tear gas while the rioters' main tactic was to set fire to bins, booths and barricades.

One interesting sub-plot to these riots, incidentally, is a new tool: the burning bicycle. Ordinary bikes don't catch fire, of course, but an e-bike can go up like a firework courtesy of its lithium battery. 

All over Paris yesterday, at every e-bike collection point, I found clumps of gnarled grey cycle frames and charred wheels piled up like artefacts from Pompeii. British cops, take note.

And with the police preoccupied, of course, next came the looting. Again, this was something entirely beyond the norm – in terms of both scale and location.

It was nationwide and, in each city, it was not confined to the banlieues, the outlying troublespots populated disproportionately by ethnic minorities and the poor. Here in Paris, the looting was right in the heart of the most prosperous shopping districts.

An entire branch of Hermes lay pillaged, its trademark orange bags and boxes scattered down the street. Chanel and Christian Dior received the same treatment. A mob ran wild in Galeries Lafayette, the Parisian answer to Selfridges or Harrods. An estimated 1,500 stores across France were plundered.

Yesterday, business was brisk on clothing websites such as Vinted as customers noticed a rush of good-as-new top brands on sale in France (plenty of choice – surprise, surprise – for fans of Hermes).

Anyone tempted to scoop up a job lot of Yves Saint-Laurent nail polish at €2.54 (£2.14) a pot might first wonder whether they are likely to receive what they pay for from a brazen criminal, not to mention the ethics of buying stolen goods.

Here, though, we come across an alarming lack of basic decency – both on social media and on the streets. 'It's only taking from the very rich,' is a popular sentiment.

In other words, all this amounts to victimless crime.

In the Place de la Republique, one of the capital's main demonstration points, the famous statue of Marianne (the personification of France) is defaced from head to toe in graffiti. 

The base of her pedestal has been smashed with sledgehammers to produce projectiles for throwing at the neighbouring military barracks. Two days on, no attempt has been made to remove a huge yellow vest draped over Marianne proclaiming (in French): 'The Police Mutilate Schoolchildren'.

Here I meet Celian, 21, a fourth-year Paris University journalism student of African-Italian heritage. A calm, intelligent man, he argues that most of the weekend's violence is acceptable.

'The police are perpetuating physical violence against us and the wealth distribution is not fair. So, yes, this is legitimate. Whether as students or as workers, we try to talk with the government by legal and fair ways, but the government doesn't talk or listen.'

Does that justify ransacking a shoe shop? 'Those people who do that are just opportunists, not part of our movement. I don't think people should invade small shops run by people with no connection to capitalism. But if people attack Starbucks or Nike, then that is a political statement because of their connection to Israel.'

He heard President Macron's televised appeal for calm and orderly debate but he rejects it. 'What we have learned from the Gilets Jaunes is that you must always keep moving. Never stay in the same place so the police cannot contain you. As Jean-Luc Melenchon says, we should "be like water".'

The Left-wing leader himself has distanced himself from the thieving, saying 'those who share our movement have no business in looting'. He fiercely rejects the government's claims that his lot are to blame: 'The real culprits are in government, unable to ensure both public order and the right to protest.'

All over Paris, there are two sounds: police sirens and the drills of the repair teams boarding up smashed windows. It will be months before the glaziers can replace all the glass.

The Lego store at Les Halles – France's biggest shopping mall – is already a wall of panneaux (wooden panels). The front of Adidas and Nike are following suit when I walk by.

Another video was going viral yesterday, that of an elderly optician called Madame Ye, who moved from China to France years ago and raised a family here. She had closed early on Saturday, pulled down the shutters and gone home but, to her horror, could see marauders smashing their way in to the small shop on the Boulevard de Magenta. She rushed back.

A TikTok video captures her in shock leaving with the last tray of glasses. What it does not show is that, moments later, even these were snatched off her by masked men.

I meet her son, William, 28, a newly qualified optician, and his sisters, Vanessa and Lea. The latter is in tears as they survey the wreckage.

'It is our only shop,' says William. 'All the family savings went into this. We've only been open a year. Our insurance won't cover this. I don't know what we do now.'

Family friend Zinadine Aidel, 27, is beyond furious. 'These are the small businesses who pay the benefits of these casseurs [looters],' he tells me.

Donald Trump has blamed this carnage on 'immigrants' but he is wrong. The protesters are from all faiths and backgrounds.

Most of the looters are, indeed, from ethnic minorities but they are certainly not the asylum-seeking small-boat crowd heading for Britain.

They are French-born, French-speaking French nationals: the children of second or third-generation migrants who came to build a better life here. And they are not going away.

Back in Les Halles, I meet Gabriel, manager of the Levi's jeans store. Having wisely had his windows boarded up before Saturday's chaos, his shop was unscathed, although it hardly looks very inviting.

When will he take the panels down? 'Oh, not yet. We have more protests in two weeks. They will be worse.'

The same marches are now scheduled all over again for the end of the month.

For the whole of France, Halloween has suddenly become very much scarier.