The French communications giant Orange and seven former or current managers are being tried for harassment because of a wave of employee suicides a decade ago.
France's main phone and Internet company saw 19 suicides, 12 suicide attempts and eight cases of severe depression among employees between 2007 and 2010.
Several previous reports indicated that the company, then called France Telecom, was undergoing a downsizing and restructuring.
The trial in Paris, which began on Monday, is the biggest case in France that leads to corporate harassment.
The charge can be punished by one year in prison and a fine of 15,000 euros.