Louise and Martine Fokkens are the subjects of a recent film and a new book about their life together as 'window girls' – and more than happy to talk about their new-found celebrity

Neither Louise nor Martine Fokkens fit the stereotype of a window prostitute in Amsterdam. The majority of women working in the most notorious public brothel scene in Europe are young, conventionally attractive and from outside of Holland. The Fokkens are 70-year-old identical twins, and very Dutch.

Known as the "oldest window girls" in Amsterdam, Louise and Martine have almost 100 years' experience of prostitution between them. They have been the subject of a well-received film aptly named Meet the Fokkens and have written a book about their lives, due to be released later this month.

I travel to meet the twins and to be given a guided tour around the legalised sex industry that attracts thousands of British sex tourists every year. The sisters dress and speak identically, and, to complicate matters, often talk over each other, in a way that is almost impossible to understand. They seem to speak in a kind of code. But they are warm and eager to talk to me.

"I was beaten on to the streets by my husband in my early 20s," Louise tells me when we meet in a tapas bar on Warmoesstraat, in the heart of the red-light area. "He told me unless I earned money for him he would leave me, and I had children and loved him, so I had to do it."

Louise has three children, and some or all have been in and out of foster care. It is difficult to get the exact story because Martine, who has four children, interjects with tales of losing her own offspring and the heartache that ensued. It could be that one tells the story for both, or they tell each other. But both have encountered violence, abuse and exploitation, and their early years in prostitution were hard. "We kept each other company," says Louise. "But Martine needs to carry on because there is not much money around."

Louise, who left prostitution two years ago due to arthritis ("I could not do sexual positions") tells me how things have changed for the worse since she entered the sex trade. "There are few Dutch women and no sense of community these days," she says. The legalisation of brothels in 2000 has not improved prostitutes' lives, in Martine's opinion. "There is no point working just for tax. That is why the girls are working from the internet and from home – you are less likely to be spotted by the taxman. The whole family used to live off your earnings and now the tax office comes up with crazy amounts you have to pay. It is better for the pimps and the foreigners, but not the Dutch girls. The vultures came in 2000. Organised criminals. They thought, ahah, it is legalised. Now we are OK."

When Louise began working, Martine was in hospital having her first child. "My mother came in and said, "You know Louise is [in prostitution]. I was in shock. I wanted to help her."

"Later on they needed a cleaner in the brothel and Martine took the job and the men asked her for business," says Louise. "So we started doing threesomes, and that was how we ended up working in the same house [window brothel] together."

The relatively rosy picture the twins paint of prostitution is perhaps because they have always looked after each other and, unlike the majority of other women, even saw punters together. Born into an ordinary middle class family with seven children in total, the twins enjoyed a happy childhood. But it all changed when Louise married a violent and controlling man.

Did Louise find the work easier with Martine by her side?

"Oh yes," they say in unison. "We are always together. We do everything together."

The sisters live on the outskirts of Amsterdam and Martine still commutes into the city three days a week. I ask how busy she is. "Yes, yes, so-so," she says. "My regulars want to know they will get a good service."

It is almost impossible to get a sense of whether the twins regret their lives in prostitution underneath the joie-de-vivre attitude both have adopted. The only time they both stop laughing and teasing each other is when Louise tells me about the shame she brought on her family when caught soliciting on the streets.

"Our mother drove down to the canal where we were working on the street and shouted: 'I see you! Your father is coming.' She hit me. I was very embarrassed for my parents."

I ask if she saved during her working years. "I have €5 in my purse," she says. "Whores are expected to do things for nothing." Unsure of what she means, I ask why the sisters do not charge for posing for photographs with the endless stream of men who approach them. "That would not be right," is Louise's response.

The sisters obviously relish their fame, and glow with pride when they are recognised by the public. I have a sense that they are viewed as celebrity oddities, and that the men will show the photos around for a laugh, although with prostitution being so public and normalised in Amsterdam, it's hard to tell.

In front of the Oude Kerk (Old Church) on Oudekerksplein we come to a bronze statue in honour of "sex workers around the world", titled Belle. The sisters are asked by a group of labourers to pose with them. Martine says she has no retirement date in mind, and Louise interjects with: "She has no money to retire yet." The image captured on camera, of two happy old women, seemingly without a care in the world, belies the abuse and social exclusion endured throughout two extraordinary lifetimes.

Ouwehoeren Op Reis (Travelling with the Fokkens) is published by Bertram & de Leeuw.

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