Further down the street, there was a flurry of activity. A woman was surrounded as she opened a huge bag full of phones, shoes, sunglasses and handbags — clearly stolen from tourists or Parisians. The goods were quickly sold and the crowd melted away.

Unemployed or underemployed Muslim migrants (and there are many) who are legal can count on a cornucopia of benefits provided by the French state, including free or subsidized housing, free medical care, free education, family allowances, and unemployment benefits. Even illegal ones manage to receive some of these benefits, such as free medical care through Aide médicale d’État.

The appalling attacks in November 2015 by home-grown Islamic State killers shone a pitiless spotlight on the problems that can grow out of immigrant ghettos.

Police have reportedly admitted the area is a ‘no-go’ zone, and will only drive through the areas armed and four to a vehicle….

These are not ”immigrant ghettos,” but “Muslim ghettos” (which include Muslims born in France).

The carnage started close to the Stade de France, the national sports stadium, which is in Saint-Denis, where some of the killers sought refuge after the attacks.

One hundred and thirty people died in a single night of violence involving suicide bombings and Kalashnikov fire around bars, cafés and venues, including the Bataclan concert hall.

Five days after the attacks, the suspected mastermind was run to ground in an apartment by hundreds of security officers….

‘The terrorists had rented rooms with no questions asked, and were left to get on with their crimes.’…

There are around 350 known jihadists living in Saint-Denis, while 1,700 are believed to have returned to France after fighting for IS in Syria, with 15,000 terrorism suspects in France.

In Saint-Denis itself, there is a record number of mosques — 160 official ones, and many more unofficial — compared with 117 Catholic churches and 60 Protestant. Yet it is the unauthorised mosques — set up in basements and garages — that the authorities fear the most.

The radicalisers use these hidden places of worship to influence the young and impressionable,’ said a veteran police officer who has worked in Saint-Denis for more than two decades.

He added: ‘Salafists (followers of an extreme form of Islam) impose the rule of religion, so we can have very little influence. These radicalisers are the ones who motivate the young towards terrorism.’

Much of the money-raising activity comes from drug-dealing by gangs, many of them Muslim. At one high-rise block of flats not far from where I was staying, the scale of the operation was evident.

Like a department store, different drugs are sold on different floors. Moroccans and North Africans sell hashish for ten euros a bag on the third floor….

At this point, I told one of the men I was a journalist and asked whether we could have a chat.

A chunky character in a red Ellesse sports shirt, he was relaxed, smiled at me and said politely to me in English: ‘No — go.’ I went.

Most blocks seemed to have the same operation, with youths guarding the front doors, ‘spotters’ on the streets opposite for signs of police or other gangs, and the drugs held and sold inside.

Rabbi Yisroel Belinow, 50, is either a fool or very brave. As I walked near a mosque, I saw him looking out of his window. His home was firebombed in 2009, and a kosher restaurant next door burned down….

‘The problem is people coming to France and wanting to change it. And it’s worse because they want to force people to change. I know I look different. The hatred is obvious — people spit when you walk past….

‘It wasn’t always like this. In the beginning, [French people] wanted to help. The charity these people [recent migrants] were shown was tremendous. But you wake up and realise pretty soon that this works one way only. Many people have left.’…

Women suffer the most. Not far from the drug dealers outside the station, I visited a women’s refuge set up by Ghada Hatem, a senior gynecologist, who says almost one in five of her patients have been victims of female genital mutilation (FGM) — the barbaric ritual of cutting the sexual organs of young women….

Sarah Oussekine, who has an Algerian background and who runs a group called the Voix d’Elles Rebelles (Voice of the Female Rebels) in Saint-Denis, says: ‘When you ask girls why they are starting to wear the headscarf — and many more are — they tell you it is an act of faith, but actually when you dig deeper, they have to wear it to stay safe.’…