Officially, they came to Japan for training, but in reality, they were forced to work long hours for little pay.
A Japanese court on Monday ordered a sewing company and an employment service to pay 4.4 million yen (52,250 dollars) in damages, ruling that the firms had exploited four Chinese interns.
The High Court in the south-western city of Fukuoka thereby confirmed a lower court ruling and also ordered the factory in Amakusa to pay an additional 12.8 million yen in unpaid wages.
The four interns went to work at the factory in 2006, and for a year, they were forced to work from 8:30 am to as late as 3 am the next morning. They had two or three days off each month.
The case put a spotlight on conditions for foreign interns in Japan and could lead to improvements in their working conditions.
The three-year training programme that the plaintiffs were involved in was introduced 20 years ago as a way to help workers from developing countries develop their skills in Japan and take them back to their home countries, but critics said many of the interns are unskilled labourers who are forced to work for low pay.
Many of their employers are struggling small firms who find few Japanese willing to work for the wages they offer. For them, the internship programme was a welcome one, allowing them to lower their wage costs.
But the programme has also had deadly consequences for workers. The Asahi Shimbun newspaper said that in the 2008-09 fiscal year, which ended March 31, 2009, 34 foreign interns died, 16 from heart attacks or strokes, an occurrence that critics said was the result of overwork.
As a result, a minimum wage for foreign interns was introduced in July and employers warned about exploiting such workers, but critics complained that the structure of the programme remained unchanged. The interns are protected by labour laws but many are still unfairly treated, they said.
Japan is seeing a demographic change at the moment. Its ageing, shrinking population has resulted in a shortage of workers in many areas. Immigration as a solution remains a taboo in Japan.