The former Elf CEO was questioned by a Togolese judge for about three hours Monday, following his lightning-fast extradition from Ivory Coast over the weekend.
His legal team had condemned the international transfer, which came the day after his arrest in Ivory Coast's economic capital Abidjan on Friday as he tried to board an Air France flight to Paris.
The Togolese hearing was expected to resume at a later date. Floch-Prigent did not immediately enter a plea but one of his lawyers, Rustico Lawson-Bankou, says his client is innocent.
The probe involves a complaint from an Emirati businessman who alleges he was the victim of a $48 million (€37 million) fraud. The purported victim, Abbas Al Yousef, claims Le Floch-Prigent was acting as his personal adviser at the time.
The case involves accusations that a network claimed to have access to $275 million in a Togolese account left by former Ivorian military ruler Robert Guei, who was killed in 2002.
Al Yousef, who manages investments, including in the oil and gas industry, alleges the $48 million was embezzled from him in the affair.
Togo's former minister of territorial administration, Pascal Bodjona, has also been charged in the case, as well as Togolese businessman Bertin Sow Agba.
Following Le Floch-Prigent's extradition Saturday, another of his lawyers Patrick Klugman denounced the move, saying extradition procedures did not appear to have been respected.
He had earlier condemned the transfer as a "kidnapping" but later backtracked from the remark.
An Ivorian prosecutor however said the transfer was an operation between two police forces in line with Interpol rules.
Klugman also claimed his client was caught up in an internal Togolese political affair. He said he feared for the health of Le Floch-Prigent, who turns 69 this month and has a medical appointment in France on September 26.
Le Floch-Prigent, currently an oil industry consultant, has already served jail terms in France for corruption which dated from his time as head of Elf from 1989 to 1993.
Several Elf senior managers were jailed after a corruption scandal that broke in the 1990s. The company was taken over by French oil giant Total in 2000.
Togo, a nation of six million people under French control prior to independence in 1960, has been run by the same family for more than four decades.
The military installed President Faure Gnassingbe in power after the 2005 death of his father Gnassingbe Eyadema, who had ruled the west African nation with an iron fist for 38 years. He has since won elections in 2005 and 2010.