European police forces say they have dismantled a vast criminal network that was exploiting illegal migrant workers in France.
Between 100 and 150 construction workers from Moldova were smuggled across Europe to work on French building sites, authorities said.
A total of 38 people have been arrested in France, Romania and Moldova for their alleged involvement in the trafficking.
The arrests were carried out during a joint "day of action" following an investigation by the French, Romanian and Moldovan police, supported by Europol and the European judicial cooperation unit, Eurojust.
"The criminal network smuggled and registered the Moldovan workers in France with fake Romanian documents while keeping their real passports as a guarantee," Europol said in a statement.
According to the agency, French authorities had suspected an organised crime group was involved in "migrant smuggling, human trafficking for labour exploitation, document fraud, social benefit fraud, and money laundering".
Simultaneous raids were carried out on Monday at 51 locations across the three countries - 17 in France, 14 in Romania, and 20 in Moldova.
Twenty-eight of those arrested were in France, while a further seven people were detained in Moldova and three others in Romania.
Authorities also seized "19 vehicles including 15 high-end cars, 2 jet skis, weapons, phones, [and] about €100,000 in cash," Europol said. Eleven bank accounts were also frozen.
An investigation into the criminal network began in 2018 after officers in France intercepted a van transporting ten "irregular" Moldovan migrants, some of whom had counterfeit Romanian identity cards.
"The criminal group, organised by a Romanian national living in France, smuggled at least 40 Moldovan nationals to exploit them in the construction business in France," Europol said.
"Most of the smuggled individuals had a low level of education and therefore were more vulnerable to exploitation. They worked 55 hours a week for €60 a day."
Eurojust added that the illegal workers were paid the French minimum wage, but that their weekly working hours greatly exceeded the legal amount, "undercutting fair competition in the building sector".
Large companies in the construction and renovation sector were also involved in this "extremely lucrative" and "criminal" scheme, the EU police agency said, with illegal profits estimated at nearly €14 million.
The Romanian owner of several French construction companies was among those arrested.
"The suspects laundered the criminal assets through eight shell companies, most of them based in France," the statement added.
The joint-investigation team was set up and financially supported by Eurojust last year, they said in a statement.
Romanian police added their role in the operation was support by the country's Special Operations Directorate.