Kampala, Uganda

The Soothing Spot has Muzak, gurgling fountains, and a friendly local staff. By all accounts it is a legitimate, happy-ending-less massage parlor. No matter. A few months after opening in an upscale mall, management began photocopying ID cards and blanketed the waiting room with posters warning that untoward advances would not be tolerated.

“Customers were expecting a different type of massage,” a manager told me last summer. “A sexual kind.”

Why the grabby hands? Locals point to Chinese massage parlors and brothels exploding across the city: Apple Spa. KLA Entertainment Center. Chinese Beauity [sic] Parlour, which sits across the street from the European Union’s offices.

The influx of Chinese prostitutes is a continent-wide phenomenon, argues Basile Ndjio, the author of a forthcoming paper in Urban Studies. He estimates that between 13,000 to 18,500 Chinese sex workers are currently in sub-Saharan Africa.

As China moves into Africa—building highways and stadiums, striking oil deals, and opening special economic zones—practitioners of the world’s oldest profession have followed, catering to both Chinese expatriates and locals. Growing African purchasing power helps explain sex migration. Deloitte estimates that Africa’s middle class has tripled in the last over the last three decades. That means more money for imported televisions, imported handbags and, yes, imported sex. Africa is “a new El Dorado for the prostitution business,” Ndjio writes.

Ndjio, an anthropology professor at the University of Douala in Cameroon, is perhaps the only academic studying the phenomenon. He stumbled on his specialty by accident while putting himself through graduate school in Cameroon with work as a casino croupier. Dealing hands of blackjack and poker to Chinese expatriates, he learned through boozy conversation and late-night confession that “Shanghai beauties”–as they are known in Cameroon–congregated in the back rooms of Chinese restaurants, hotels and lounges.

Gamblers taught him the code words–asking for “stress relief,” “rest” or “acupuncture”—to go behind the curtain and penetrate the cliquish, guarded world of Chinese expatriates in Africa. Prior to his current paper, Ndjio has over the past six years authored two of the only studies on Chinese sex migration to Africa.

When I visited Ndjio at the Institute for Advanced Study, in Princeton, New Jersey, where he is halfway through a yearlong research fellowship, he explained that Chinese prostitutes first arrived in sub-Saharan Africa during the Cold War almost exclusively serviced migrant workers working on PRC-funded construction projects.

In the second, current phase–which began in the early-2000s–migrant sex workers joined the influx of inexpensive Chinese goods and services into Africa and began servicing locals. In Cameroon, Chinese prostitutes now compete with local women all along the price spectrum–from $50 at upscale brothels to a thousand francs ($1.75) on street corners.

Just as Zambian chicken farmers and clothing retailers in Lesotho resent the one million Chinese who have relocated to Africa since 2001, Nadjio says, so too do local prostitutes balk at Chinese women selling sexual exoticism at cut rates. In the resulting guerre de sexe, as Cameroonian papers dub the clash, local sex workers label their Chinese counterparts putes sorcières (“witch-bitches”), appeal to their customers’ sexual patriotism, and sometimes resort to violence.

“There is a feeling of invasion and yellow peril,” Ndjio says. “You would think there were ten times as many Chinese sex workers.”

That sex should join China’s list of exports is perhaps unsurprising: the prevalence of prostitution in the Middle Kingdom has exploded over the last two decades. The country has as many as 10 million sex workers—roughly the population of Greece—working in massage parlors, bathhouses and karaoke bars. The southeastern city of Dongguan (population: 8 million) alone has perhaps 300,000 prostitutes.

Is Chinese sex labor migration to Africa and beyond forced or voluntary? Around the globe, many women work in prostitution rings run by Chinese pimps and protected by corrupt local officials. The US State Department’s Trafficking in Persons Report for 2015 listed China on its “Tier 2 Watch List” for countries with significant or increasing human trafficking volumes.

Anecdotal research suggests a more nuanced situation. In Cameroon, Ndjio has found that most Chinese sex workers are rural women that move abroad for gigs as waitresses and secretaries, only to arrive and find traffickers demanding sex work for the repayment of plane tickets and visas. But he also notes several highly publicized cases in which police have “freed” Chinese sex workers from prostitution rings, whereupon the women declare they prefer to stay in Africa. Realizing how much money they can earn, some sex workers move on to Cameroon’s more prosperous neighbors Nigeria and Ghana to earn more.

Whatever the circumstances of their arrival, prostitutes have gifted China an unexpected soft power: their ubiquity is changing local beauty norms.

“Girls go to salons with photos of Chinese models and say, ‘make me look like her,” Ndjio says. “To have a ‘look chinois’ is a compliment.”