The first former Telecom executive to be placed under investigation was Didier Lombard, who was the company's CEO from 2005 to 2010. He was told by police Wednesday that he was being investigated for workplace harassment and put on a 100,000 euro ($125,000) bail.
On Thursday, the company's former head of human resources, Olivier Barberot, and Telecom's former second-in-command, Louis-Pierre Wenes were also due to appear before the magistrate.
France Telecom itself could also be placed under investigation.
With Lombard at the helm, France Telecom shed more than 20,000 jobs, a decade after its privatization.
In 2012, the SUD trade union said that the company was intentionally pressuring employees to quit in an effort to reduce costs by cutting its work force. The union said forced moves and unobtainable performance targets were partially to blame for the high number of suicides.
In February 2010, government labour inspectors wrote in a report on the suicides that France Telecom had ignored warnings from doctors about the mental health of certain employees. The report had warned that restructuring was having a "pathological effect" on staff morale, according to the news agency Reuters.
Lombard faced questioning for two hours on Wednesday before being released on bail.
In an article in the newspaper Le Monde on Wednesday, Lombard wrote that "I forcefully reject the idea that (restructuring) plans vital to the survival of the company might have been the cause of human tragedies."
If convicted, Lombard could face a fine of 15,000 euros and up to a year in prison.
mz/ipj (dpa, Reuters, AFP)