The 29 are accused of smuggling drugs and arms after a long police operation that involved phone taps and surveillance of the alleged criminals.
The principal suspect is Camille Abboche, 45, a former office holder in the Catholic trade union, the CFTC, at the company.
He was arrested in 2013 and has been in prison awaiting trial since then.
Abboche is alleged to have recruited ferry workers to smuggle guns and drugs to gangsters on the island and used his right to circulate in ports without going through customs to carry out the trade.
The defendants deny the charges, although during interrogation Abboche admitted agreeing to transport "bags or vehicles" to Corsica as a favour to friends.
Police say they seized cocaine, 80,000 euros in cash and several guns at his home and office.
They even suspect him of plotting with Christophe Anziani, at the time a wanted criminal who was in hiding, to murder two Corsican brothers by booby-trapping their car.
It rejected existing offers to take over the company and fixed a new date in September to see if any better ones would be made.