A file photo of Finau Maka.
Maka, who is playing for Toulouse, was arrested and released this week by French police after his alleged victim complained to authorities.
Maka was born in Tonga but grew up in New Zealand where he played for the Blues, the Highlanders and the Hurricanes before heading to France.
The French newspaper Le Parisien said the Tunisian man who worked for him lived "in disgraceful conditions".
The Daily Mail reported police raided Maka's home where he lived with his wife Elizabeth and his son Brian.
A Toulouse police source told the newspaper it was a new case of modern-day slavery and that the allegations were very serious.
The alleged victim was believed to be an illegal immigrant.
