Her murderous nanny thriller gripped France, winning its top literary prize and the attention of President Macron. With Lullaby now out in English, the author shares her thoughts on motherhood, #MeToo and being a Muslim in France

“The baby is dead. It only took a few seconds,” so begins Lullaby. First we had the murderous perfect wife, Gone Girl, in 2012, then the murderous perfect husband, The Girl on the Train, in 2015, and now the murderous “perfect nanny” – the US title for the Goncourt-winning French bestseller, published in the States and the UK this month. Lullaby is ménage à trois as domestic noir; the relationship, as intimate and intense as any affair, between a couple and their nanny. It was “like love at first sight”, says Myriam, the mother, of their first meeting. Until, like a “wounded lover”, the nanny stabs the two children in the bath, before slitting her own throat. This is not a spoiler: it’s all there in the devastating opening pages.

“I tried to use all my deepest fears and all my nightmares: losing my children, living with someone I think I know, but actually I don’t know her at all,” says Leïla Slimani, who has a six-year-old son and a six-month-old daughter (and, yes, a nanny). “So at the same time as it was frightening it was also a relief because I could give all my anxiety to my reader, to you!” she laughs disarmingly.

A novel that skewers gender, class and racial stereotypes, but so gently we barely notice, Lullaby looks set to become a publishing sensation, having already sold 600,000 copies in France and with film versions in France and the US under way.

Petite and engagingly expressive, the 36-year-old Moroccan-born author has become something of a poster girl for a re-energised France: “Leïla Slimani Superstar” shouted French Elle beneath a striking photo on their cover (surely a first for a Goncourt winner), while giant pictures of her appeared on bus stops across Paris. President Emmanuel Macron lived up to his bookish reputation by signing her up as an ambassador for Francophone affairs (she reportedly turned down his offer of the role of culture minister). “Everyone was exhausted with these old men giving us lessons,” she says of the new political regime. “It is very refreshing to see this new generation: a lot of women, a lot of young people.”

Slimani grew up in Rabat and her family had a live-in nanny, 'but I knew she was an employee'

Infanticide, female sex addiction (the subject of her 2014 first novel, Dans le Jardin de l’Ogre, inspired by the Dominique Strauss-Kahn scandal) and a non-fiction book of first-person testimonies about the “sexual miseries” of Moroccan women – Slimani’s oeuvre is slim, but fearless. “Everyone asks me ‘Why do you choose such subversive or shocking themes?’, but when I’m alone in my office, I’m not like, ‘OK I’m going to shock’. I want to write about a character who fascinates me, someone who I don’t understand.”

Lullaby might begin with the murders, but she set out, rather more mundanely, to write about the ambiguous figure of the nanny. “Who can really say, ‘I know my nanny’?” Slimani asks, sending a chill through every working parent’s heart. “Everyone tells her, ‘You belong to the family’ but everyone knows that she doesn’t.” She grew up in Rabat and her family had a live-in nanny, whom she called her Mouima, little mother, “but I knew she was an employee. If she did anything wrong, my mother or father would tell her, ‘You have to go’.”

Facebook Twitter Pinterest Slimani with President Macron. Photograph: POOL/Reuters

But the nanny’s lot, it turned out, made boring fiction: “You go to the park, you make food, you change nappies, so after 100 pages I was like, OK and now?” The “and now” turned out to be the discovery of the real-life murder of two children by their nanny in New York in 2012. “Woah! I thought, I have to start with this,” she says, revealing more than a splinter of ice. “Now the reader is going to be very interested in this very normal family.”

Slimani’s Greek tragedy – we know it ends badly – creates a powerful double perspective: the reader’s terrible foreknowledge undercutting the parents’ fatal ignorance as they entrust their whole world to this “miracle” nanny. It’s hard not to read the novel as a symbolic punishment of the mother and father’s reluctance to relinquish their old lifestyles. Was that deliberate?

“No, not at all,” she insists. But she did want the reader to ask the question. Her character is known only by her first name, Louise, after the British nanny Louise Woodward who was convicted of involuntary manslaughter in the US in 1997. She remembers the implication made by the defence lawyer in that case, that if the mother, a doctor, had “wanted her children to be safe, she should have stayed at home”. By making us complicit in casting judgment on the parents, Lullaby probes our enduring fears and prejudices about working mothers.

“We are the first generation of women to whom everyone said: you can have it all – you can have a career, you can have children, you can marry or not marry, you can divorce. Wow, it’s so amazing! But no one gives us the mode d’emploi, the way to do everything. It is too hard,” she says.

Here are the messy contradictions of motherhood: the intensity and the boredom; the hunger for your children and the sense that “they are eating me alive”. Slimani wanted to capture “the anxieties and claustrophobia of being a mother”, and the book’s suffocating pull leaves the reader longing to come up for air.

“When you are a little girl everyone tells you that when you are a mother you are going to be so fulfilled with love, you will never feel lonely any more, you will want to give everything to your children,” Slimani says. The reality, of course, is that there is also “a lot of anxiety, moments of depression, moments when you just want to have a break and go out of your house and be someone else, become who you were before. But it’s a kind of taboo.”

Lullaby by Leila Slimani review – a truly horrific, sublime thriller Read more

While the novel shines a “light here and there” on the nanny’s sad backstory, it was important that she remain a mystery at the end. Significantly, Louise is white, while Myriam, like the author, is from Morocco – although this is carefully understated, just part of the casual racism and snobbery at play in unexpected ways. “I felt it very important to say that sometimes the boss is an immigrant, and that sometimes the poor are white,” she says. “This made it violent as a social relationship.”

As the only white woman, Louise is the stranger among the already estranged community of immigrant nannies. “When she goes to the park, she’s always alone because she doesn’t speak the same language, she doesn’t come from Africa, or from Ukraine, and I think that is why she commits this act, because she belongs to nowhere and no one. She is at the bottom of society, she is a woman and she is poor. She is no one.”

It is very important for women to break the silence and to stop being ashamed

The bleak depictions of the park will give anyone who’s shivered by the swings a pang of recognition. And it was here that Slimani first had the idea for the novel: “As a writer you don’t only work in an office, so in the afternoon I wander in my neighbourhood and I go to these playgrounds. In the winter it is very sad because you can see all those African women in the traditional dresses but with a big coat on and they are very cold and the children are very cold in those dirty playgrounds.”

Slimani came to Paris to study when she was 18, and fell in love with the city, “but not with the romantic Paris. What fascinates me is the loneliness, the poverty, it’s a violent city. There is something very dark here, especially where I live in Pigalle. It is the district of sex, of eroticism, there’s a lot of immigration. I wanted to show this place.”

Although a date is never mentioned (the external world is glimpsed, filmy and distant, from within the bubble of looking after small children), this is Paris 2015 – at dinner parties, people talk about “their jobs, about terrorism and property prices” and Myriam forbids the children to watch television after the terror attacks in the Bataclan concert hall and elsewhere in the city. “It was a very difficult year,” Slimani concedes. “It was very violent. Being an immigrant at this time, being a Muslim at this time was a very particular experience, sometimes very sad, sometimes you could feel very humiliated by the way people talked about origins or Islam. How can I use all this atmosphere to build Louise and her loneliness and her madness?” she asked herself.

Facebook Twitter Pinterest A large crowd gathers to lay flowers and candles in front of the Carillon restaurant in Paris, two days after the terror attacks on 13 November 2015. Photograph: Ian Langsdon/EPA

Slimani worked as a reporter for the weekly journal Jeune Afrique, which was useful training for becoming a novelist, she says, because you have “to observe people, pay attention to details”. Following the birth of her son, it seemed it was finally time to make good her mother’s prediction that she would be a writer one day. Her family enrolled her on a creative writing course, and she gave herself two years.

When I write I’m not a woman, I’m not a Muslim, I’m not a Moroccan. I can reinvent myself and I can reinvent the world

Her first novel, written in the wake of the Arab spring and set in Morocco, was refused “by every editor in Paris”. They were right, she says now, “it was a total failure”, but that setback freed her from the burden of identity politics. She wrote Dans le Jardin de l’Ogre about as far away from “camels and deserts” as it’s possible to get. “The public and the critics were a little bit surprised that as a Moroccan young woman I was writing about sex and about a French woman in Paris,” she says.

Slimani has been criticised (in her former paper) for choosing such provocative subjects, but following the publication of the non-fiction Sexe et Mensonge: La Vie Sexuelle au Maroc (2017), she also received “tonnes” of grateful letters from Moroccan women. The book was published just before the emergence of the #MeToo campaign, and she says: “It is very important for women to break the silence and to stop being ashamed, because the silence is always good for those who harass, for those who are violent, for those who dominate.”

Reading Lullaby feels like a nightmare from which you emerge, as Louise wakes from a heavy sleep, “feeling sad, disoriented, your stomach full of tears”, and the experience of writing it was draining. But its success “is a dream that came true. When I was a little girl and people would ask me what I wanted to be when I got older I always used to say I want to be paid to think. So for me to dream, to think, to write – it is wonderful.”

She is working on another novel, but isn’t telling … Is it going to be shocking? “I hope so!”

Writing has been a profoundly liberating experience for Slimani. “For me, it is freedom, freedom from everything: when I write I’m not a woman, I’m not a Muslim, I’m not a Moroccan. I can reinvent myself and I can reinvent the world”

• Lullaby is published by Faber. To order a copy for £9.74 (RRP £12.99) go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.