Prosecutor Xavier Tarabeux in the southern city of Marseille said Trabelsi had been charged with "aggravated fraud and money laundering in an organised gang."
Officials gave no other details of his arrest.
Tunisia said Sunday it was seeking Trabelsi's extradition to face charges of fraud.
A Tunisian justice ministry statement said he faced 17 arrest warrants in Tunisia and 43 international warrants.
The millionaire businessman and brother of Ben Ali's wife Leila Trabelsi left Tunisia in January 2011 when the Arab Spring uprising forced the veteran leader to flee to Saudi Arabia.
Trabelsi and his family flew in a private jet to Montreal where he requested political asylum but Canada turned down his appeal in 2015 , and a year later as it prepared to deport him he vanished.
A leaked June 2008 US diplomatic cable concluded that Trabelsi was "the most notorious (Ben Ali) family member and is rumoured to have been involved in a wide range of corrupt schemes".
Trabelsi -- whose holdings included an airline and hotels -- has denied the allegations against him, saying he accumulated his wealth from being a successful entrepreneur.