Everyone has an opinion about where Felicia Anna works. For the last nine years, the 33-year-old Romanian sex worker has attracted clients by standing in the glowing windows of the world’s most famous red light district. Sipping coffee outside a cafe on one of Amsterdam’s cobbled, canal-side streets, she says the area’s reputation means it attracts far more controversy than legal prostitution does in other areas. “We’re always in the public eye, literally” she says, laughing. (TIME has used pseudonyms to protect the identities of sex workers interviewed for this piece.)

Named “De Wallen” (The Walls) in Dutch for its position inside the old city walls, the red light district’s medieval buildings have been a hub for sex workers since the 15th century—long before the Netherlands legalized brothels and began regulating and taxing prostitution in October 2000. Today, escort services and sex clubs make up a significant part of Amsterdam’s sex work sector. But De Wallen’s window brothels—popularized in the 1960s as authorities grew more tolerant of women opening their curtains to attract clients—remain iconic: the literal manifestation of the clear-eyed Dutch approach to activities that other countries would rather sweep under the rug.

In the years since Felicia Anna arrived in this city of 850,000, though, a crisis has been building that leaves the fate of the red light district uncertain. Budget tourists have flooded the streets of De Wallen, often snapping photos of sex workers without permission and crowding out residents. The increasing numbers of migrant workers from Eastern Europe and further afield since the late 20th century—advocates estimate around 80% of those working in the windows are migrants—has fueled concerns among lawmakers over sex trafficking. And, on an international level, the Dutch model of legalized, visible sex work hasn’t gained as much traction as the controversial Swedish model—implemented in 1999 and recently copied by Canada, France, Ireland, and Israel—that criminalizes the buying, but not selling, of sex in a bid to drive down demand. In the U.S., full decriminalization bills introduced this year by New York State and Washington D.C. legislators face a long road and fierce criticism—including from some sex worker advocates.

Femke Halsema, Amsterdam’s first female mayor, says she is determined to see Dutch pragmatism prevail in her city, despite the red light district’s difficulties. “I don’t have to like sex work. It’s irrelevant. Because there’s a market,” she says. Halsema has ruled out a city-wide ban on sex work but says the red light district must fundamentally change: crime must go down, residents must have a quieter life, and sex workers must have safer working conditions. In July, she announced four possible options for reform—including the closure of all 330 windows and the end of prostitution in the red light district. That idea has angered sex workers and their unions, who say it would drive them into more vulnerable underground conditions and damage the livelihoods of tax-paying workers. “We are a part of Amsterdam. We were here first,” Felicia Anna says. “Do we always have to move away, just because some people don’t like it?” To solve the red light district’s crisis, Amsterdam will need to decide how the world’s oldest profession should look in the 21st century city.

Femke Halsema, mayor of Amsterdam, poses for a photograph in her office in Amsterdam, Netherlands, on Nov. 30, 2018. Jasper Juinen—Bloomberg via Getty Images

The mayor’s office sits just half a mile from De Wallen, in a sleek city hall of metal and glass. Halsema came to Amsterdam in her early thirties, attracted by the freedom of the big city after getting bored knowing “every face” in smaller Dutch towns. Gazing through large windows over a canal, the mayor contemplates the red light district’s role in her adopted city’s reputation. “Amsterdam has a very long tradition of protecting freedom, and being a tolerant city. And I really want to protect that,” she says; as a lawmaker in parliament in 1999, she voted in favor of national legalization. “But we do not want to be famous because of sex and drugs. We want to be famous for our cultural heritage.”

But Amsterdam’s raucous reputation likely helped to draw many of the 18 million tourists who visited the city in 2018—four times the number of annual visitors a decade ago, before Europe’s budget air travel boom. On a Friday evening in the red light district this fall, they are out in force. British women on bachelorette parties stream out of karaoke bars and into brightly lit cafes that serve Nutella on everything. Clusters of French and Spanish teenagers wander over canal bridges, swigging wine bought from convenience stores, while Australian backpackers in coffee shops sample the legal weed. Middle-aged German couples shuffle past the window brothels and snap souvenir photos, ignoring signs that warn photography will violate sex workers’ privacy. And locals furiously grip their bike handles, chiming their bells to clear a path through the throng.

Since Halsema took office in July 2018, the city has hired extra security workers to remind tourists to behave and announced a ban on organized tour groups in the area, starting in April 2020. Soon, Halsema plans to go further. To alleviate congestion in the area and combat sex trafficking, she has suggested four scenarios: the closure of window brothel curtains to discourage gawking tourists; a reduction in the number of windows; the addition of more windows to relieve sidewalk crowding or the end of prostitution in the red light district entirely. If she moved sex work out of De Wallen, Halsema says she would create a new work space somewhere else, either by relocating the windows or by creating a sex work hotel, where authorities could screen visitors.

Some argue that the city government itself is partly to blame for the red light district’s problems. Starting in 2007, a city-run gentrification project called 1012 (for the area’s postal code) bought up the leases of buildings used as brothels and cannabis coffee shops and, over the next decade, replaced them with upscale boutiques and restaurants. Around 125 brothel windows closed, increasing the concentration of tourists around the ones that remained. In the meantime, new mini-markets and other shops geared toward tourists opened up, counteracting the city’s aim of drawing Amsterdammers rather than tourists to the area. In 2018, the city’s public audit office ruled the project had largely failed.

Sex workers say that 1012 shifted the atmosphere in the red light district, turning it into a more general tourist area and making it harder to run sex-related businesses. “At the moment, there are many tourists who just come to watch, and to take pictures, but don’t want to visit them as a sex worker and pay for their services,” says Rik Viergever, a board member at My Red Light, a non-profit brothel partly run by sex workers. Felicia Anna says the new demographic, which can’t afford her prices, has forced her to take several months off work.

It also did less tangible damage. Project 1012 “completely destroyed” trust between sex workers and the authorities, says Mariska Majoor, who worked in the windows in the 1980s and has since been a writer and one of the most prominent Dutch campaigners on sex worker rights. 1012 was done in the name of reducing human trafficking and crime in the red light district. “But it felt very obvious that it was a real estate thing, about buying up valuable land for rich people. It had nothing to do with making things better for sex workers,” Majoor says.

This time, though, Halsema says conditions for sex workers are central to her reforms. “I think most Dutch people have a sentimental image in their head of the red light district as a nice, intimate part of town, where sailors come, where strong Dutch women invite them in and hit them if they’re being rude,” she says. “But the atmosphere there today is different.” Halsema claims that the surge in women from poorer Eastern European countries, such as Romania and Bulgaria, as well as other less economically developed regions like Latin America and Africa, increases the risk of exploitation. While not all of them were trafficked, she says, “you can question their free will, because there is a huge need for them to feed families elsewhere.”

Closing some windows or shifting everything to a contained, city-run workspace would, Halsema says, make it easier to monitor trafficking than in the porous borders of the red light district. In the long run, quashing Amsterdam’s reputation as a sex work hub could also send a signal to traffickers. “As a local governor I can’t end human trafficking any more than I can stop the international weapons’ trade,” she says. “But I do think there’s something to say about the relationship between being internationally known as a place of prostitution, and the attraction for traffickers.”

National figures show a striking increase in Dutch authorities’ counts of the number of victims in the Netherlands since the legalization of brothels, from 228 in 1998, to a peak of 1,711 in 2012, and 742 in 2018 ; the national rapporteur on trafficking estimates that the actual number of victims in the Netherlands is around five times the reported figures. 72% of potential reported victims in 2018 were working in sex work, the rest in sectors like construction. But the government says the fluctuation in reporting rates may be explained by the changing resources allocated to policing and social services in a given year, and the awareness of the public. In recent years, the Internet has given traffickers new ways to do business outside the view of law enforcement, further complicating efforts to accurately count victims.

It is also hard to know if the problem is worse than in other countries, warns Brian Varma, manager at CoMensha, a Dutch non-profit that gathers data on trafficking. “In the E.U., every member state has its own methods for measuring victims,” he says. The Netherlands registers everyone presumed to be a victim by authorities, including some people who have declined to be formally or legally identified as trafficked. “Other countries, for example Germany or France, only register identified victims. That is why our numbers are higher,“ Varma says.

Though Halsema concedes that the figures on trafficking are unreliable, she says she feels obligated to do anything she can to reduce trafficking in her city. “Even if only [a small fraction] are trafficked, the stories you hear are so horrible.” The websites of Dutch anti-trafficking organizations brim with victim testimonials. Many were tricked by traffickers posing as boyfriends, known as “loverboys,” and forced to work for months or years as sexual slaves. In one 2016 court case, the victim of an Albanian trafficking gang told a court she’d been held hostage with her children in a red light district brothel, suffering beatings, rapes and pressure to undergo a breast enlargement. “We cannot accept it,” Halsema says.

Despite concerns from authorities, some sex workers say the window brothels are actually one of the places they feel most empowered to do their job. Thanks to a quirk in the prostitution licensing system, the windows are the only place they can work in Amsterdam without giving a cut of their money to a brothel owner or escort agency—a rule sex worker unions have long argued is unfair. In the windows, workers pay a fixed rent of roughly 90 euros for a nine-hour day shift and 170 for a nine-hour night shift and keep the rest of what they make. “If I go to work in a club, usually the club owner would take away 50% of my income,” Felicia Anna says. Last year she started a new pressure group, Red Light United, to represent workers who use the windows. She surveyed 170 window workers and says 93% are against plans to move the windows.

Jade, 29, who began using the windows three years ago after moving to Amsterdam from outside the E.U., says that working alone in the windows allows her greater control over her money, as well as the option to turn clients away if she doesn’t like the look of them or if they are rude to her. She bristles at the mayor’s concern for migrant women. “We’re all seen as vulnerable foreign women now because we’re migrants,” she says. “But I’m very much an agent of my own life, of my migration and of my business.”

Few deny that trafficking exists in Amsterdam. Many sex workers and advocates argue, though, that the red light district is one of the safest places in the city to do sex work. Jade points out that working in the red light district, she is surrounded by her colleagues. Heleen Driessen, a counselor at P&G292, a De Wallen-based health clinic for sex workers, says the number of police, local lawmakers and social workers who visit the area regularly make it difficult for traffickers to put women to work there. “Of course, there are sometimes victims of human trafficking,” Driessen says. “But when you ask them, they are also happy that they worked in the red light area, because they could find us and ask us for help.”

Driessen says the transparency about prostitution encapsulated by the red light district is what makes Amsterdam—and the Netherlands more broadly—one of the world’s safest places to be a sex worker. She contrasts that visibility with the Swedish model, which allows women to carry out sex work but criminalizes clients and anyone who profits from another person’s sex work. Critics of the Swedish model argue it serves only to minimize the visibility of sex work, rather than to make it safer for the women who do it. Some argue it discourages sex workers from working in pairs or groups because they could be jailed for running brothels. And because the criminalization of buyers pushes people to carry out sex work in isolated spaces out of sight of the authorities, the Swedish model has been blamed for a surge in violent attacks on sex workers in France and Ireland.

A vocal but fairly small minority is pushing for the Netherlands to adopt the Swedish model to address exploitation; Christian feminist campaign group Exxpose has compiled a petition of 50,000 signatures—above the threshold at which parliament must hold a debate. Exxpose cite research that shows Swedish authorities saw numbers of women working in street prostitution was halved in the decaded following the 1999 legislation.

Though the Swedish model has taken off in seven other countries, Exxpose’s push for criminalization in the Netherlands is unlikely to succeed any time soon. In Amsterdam, the mayor is clear that she’s a supporter of legalized sex work. But some sex workers say Halsema’s proposed reforms reflect a wider pattern of allowing sex work in theory, but discouraging it in practice. “There’s so much discouragement hidden in the rules that it’s virtually impossible to be innovative in this sector,” says Velvet December, a coordinator at the sex worker union PROUD, citing an existing ban on Amsterdam’s sex workers working from home, and on window workers using the internet to find clients

December fears if the window brothels are closed, the city’s already-tight rules governing sex work will make it hard to find new space for the industry to thrive. Investors will be put off by the regulations, and people living in areas targeted for a sex workers’ hotel will protest, she says, pointing to the example of nearby Utrecht as a city that tried to overhaul its prostitution sector. In 2013, the city closed its historic red light area and around 100 prostitution windows on canal boats, promising to look for new sites for window work. Six years later the plans remain stalled because of the difficulty finding financial backers and resistance from the city council.

Relocating or replacing the red light district with a purpose-built prostitution hotel would also mean the end of an international landmark—even if it’s a controversial one. “To have the sex industry integrated with so called ‘normal life’, among churches and restaurants and a kindergarten and the Salvation Army shop – that’s pretty special,“ Majoor says, noting that the red light district developed over centuries. “You can’t just create that atmosphere somewhere else. If we get rid of the sex work, Amsterdam’s city center will be like any other old European capital.”

Halsema says she’s well aware of the danger of being too dogmatic, given the red light district’s historical roots and the concerns of sex workers, residents and anti-trafficking groups. She has held public meetings on the proposed reforms, inviting local residents and sex workers to weigh in—a step that sets her apart from previous city authorities, sex workers say. The city council will debate her ideas up, offering opinions on potential risks and benefits of each one. But Halsema will make the final choice and implement it, likely some time next year. “I want to create a process where a lot of people feel they are being heard—which is not the same as having it their way. We all have to compromise in the end.”

The shape of that compromise will likely determine what comes to mind when you hear the name Amsterdam, or even the term “sex work,” 10 years from now. For a few months though, the windows and their curtains remain open. The red lights continue to glow. And the debate rages on.

Write to Ciara Nugent at ciara.nugent@time.com.