As chalices go, few are as poisoned as the one Emmanuel Macron has just handed Christophe Castaner. Minister of the interior is one of the most challenging posts in government. The former Socialist MP has cultivated an image over the years of a political tough guy, in contrast to his predecessor, the diminutive Gérard Collomb. But what passes for tough in the National Assembly won't intimidate the tough guys in France's inner cities.

During his eighteen months in the post, Collomb was a diligent minister, but in the end the 71-year-old was worn down by the enormity of his task. He parted with a message that should cause his successor a few sleepless nights.

Explaining that he had toured the inner cities of Marseille, Toulouse and Paris, Collomb said:

“ "The situation is very difficult and the phrase 'Reconquering the Republic" is apt because in these districts it's the law of the strongest that reigns, that of the drug dealers and radical Islamists, which has supplanted the Republic."

He ended his farewell by expressing his anxiety that if something is not done today then tomorrow France will be faced with "immense problems". He elaborated on what those problems will be in one of his last interviews, with the weekly magazine L'Express. Asked if he shared the fear of the head of France's equivalent of MI5 that a civil war was a real risk, Collomb said:

“ "You always have that risk...it's not a fantasy, even if I don't like using the term 'civil war'."

The tragedy is that this isn't a new warning. France was alerted to what Collomb describes as the 'ghettoïsation' of France in 2002 with the publication of the book, 'The Lost Territories of the Republic: anti-Semitism, racism and sexism in schools'. One of its editors was Barbara Lefebvre who, instead of being acclaimed for her honest investigation, was branded an Islamophobe for daring to speak the unspeakable.

In an interview with Le Figaro earlier this month, Lefebvre compared Collomb to a captain who abandons his ship as it nears the reef. But her strongest criticism was reserved for Emmanuel Macron. The president, she said, "seems to be overwhelmed by the reality of the fractures within France."

These fractures aren't the figment of the right's imagination. Two well-known journalists from the left-wing Le Monde newspaper this week published a book that describes the extent of the Islamisation of Seine-Saint-Denis, to the north of Paris, where trade unions are now organised along religious lines, bus drivers refuse to shake the hands of their female colleagues and schoolgirls excuse themselves from swimming lessons.

Then there's the endemic violence in France: the frequent ambushes of the emergency services, the anti-Semitic murders, the homophobic assaults, the sexual harassment, the latter so bad that in Seine-Saint-Denis a scheme has been introduced where women can ask bus drivers to stop as close as is practical to their home in order to reduce the chances they'll be accosted on the street.

The mayor of Paris, Anne Hidalgo, may paint pedestrian crossings in the rainbow colours of gay pride and boast that her city is a "refuge that embraces the Republican values of liberty, equality and fraternity" but she, like her president, knows the bitter truth.

This reality was articulated in an open letter to Macron by the mother of Adrien Perez, who was stabbed to death in July outside a Grenoble nightclub in an unprovoked attack. Accusing the president of failing in his obligation to protect his people, Mrs Perez ended her letter with a cold mockery of her country, writing:

“ Liberty: It disappeared when the State proved incapable of assuring the security of each person.

Equality: It disappeared when the State consented that a murderous minority could carry on a reign of terror

Fraternity: It disappeared when the State allowed violence to govern social relations

Barbara Lefebvre believes that the situation in France is now so bad that the "tipping point is close, everyone can feel it coming".

This then is what Christophe Castaner must digest in his first week of his new job - not forgetting that other hefty file in his in-tray marked 'immigration'. The question is: will Castaner face up to the truth? Or will he adhere to what Lefebvre describes as the "progressive utopia" espoused by his boss? He's known as a Macron 'loyalist', which doesn't bode well, particularly in light of what the president said in a television interview last night. "The world is fracturing, new disorders are appearing and Europe is tipping almost everywhere toward extremes and again is giving way to nationalism," declared Macron. "Those who do not see what is going on around us are sleepwalking. Not me".

No country in western Europe is fracturing as swiftly and as deeply as France, but nationalists aren't to blame. Yet its president refuses to confront this reality. Gerard Collomb talked of reconquering the Republic but for the moment the conquest continues, by those who wish to turn the French Republic into an Islamic one.