Police said that 5,000 people demonstrated outside the court on Wednesday morning, a representative of the CGT union said there were double the number with supporters from across France and delegations from Belgium, Germany, Switzerland and Luxembourg.
The case has become a cause célèbre for the left since eight former Goodyear workers, five of whom are CGT members, were sentenced to nine months in prison plus 15 months suspended for holding two executives for 30 hours after the closure was announced.
The battle to save the 1,143 jobs at the site attracted nationwide coverage at the time.
The defendants claim they never prevented the managers from leaving the premises, although they admit the atmosphere was tense.
Goodyear and the managers involved have withdrawn their legal complaints.
As several Air France employees await the verdict in their trial over a protest in which member of company management had their clothes torn during another jobs protest, the CGT claims the Goodyear sentence is part of a process of "criminalisation of trade union activity".