(Recasts to update with managers released.)

VILLEMUR-SUR-TARN, France (AFP)--French workers angry at plans to shut a U.S.-owned auto parts supplier held two managers inside for more than 24 hours before releasing them, in the latest case of "boss-napping."

Union activists at the Molex factory at Villemur-sur-Tarn, southern France, began holding the two managers on Monday afternoon after a meeting to discuss some 300 layoffs ended in disagreement.

French labor department mediators were called in but the managers refused to negotiate while they were still being held.

The two, deputy manager Marcus Kerriou and human resources director Coline Colboc, left the plant Tuesday around 7:45 p.m. local time (1745 GMT) as about 100 workers shouted abuse and booed.

Under an agreement backed by trade unions but criticized by workers, both sides have been called to a meeting for Wednesday morning outside the factory gates to assess the situation.

Lawyers acting for Molex earlier asked a court in nearby Toulouse to order the release of the two bosses.

"There is no question of negotiating in this situation," said Kerriou.

French workers have taken several bosses captive in the past two months to demand better compensation deals for job losses, despite a threat by President Nicolas Sarkozy to put a stop to the practice.

Separately, a few hundred workers at a German-owned Continental plant went on a rampage Tuesday after a court rejected their bid to stop the factory from shutting down with the loss of 1,100 jobs.

The employees trashed offices of the regional administration in Compiegne, northeast of Paris. A judicial official said there was some damage but no one was injured.

"This is the worst outcome, we are doomed," Pierre Rubeck, a union activist at Continental, said after the court handed down its ruling.

Sarkozy earlier this month said blockading company bosses in their offices was illegal and that he would not allow "matters to go on like that."

No charges have so far been brought against any employees who have detained their bosses. In each case, the managers were released unharmed, and most of them agreed to new negotiations.

Union leaders at Molex, which produces electronic connectors, earlier said they feared that police would be called in.

"We were told that we were committing an offense," said union official Denis Parise, "But is it worse than putting 300 workers on the streets?"

Molex announced plans last year to shut down the plant which was purchased five years ago.

Unions say management has moved production to plants in the Netherlands and that the shutdown was planned well before the economic crisis.

Business leaders have urged Sarkozy to take action against "boss-napping," but the leader of France's top union, the CGT, has said he condoned the action as long as no harm comes to the managers.