Sarkozy "to save plant" after staff detain bosses

PARIS, April 1 (Reuters) - French President Nicolas Sarkozy pledged on Wednesday to save a factory run by U.S. bulldozer maker Caterpillar Inc, where staff angry over layoffs detained four managers for 24 hours.

Union sources said the managers were released at Wednesday lunchtime after spending the night locked up in the plant in the town of Grenoble in the French Alps.

Caterpillar, the world's largest maker of construction and mining equipment, plans to slash jobs in various countries and a union official said 733 out of 2,700 workers would lose their jobs at the Grenoble plant.

"I will save the site," Sarkozy told Europe 1 radio in an interview on Wednesday morning. It was not clear exactly what he meant as the site is not threatened with closure.

"I will meet this union committee, since they have called me to the rescue ... We won't abandon them," he said, referring to Caterpillar staff's labour union representatives.

The French president's approval rating fell to 36 percent in a poll issued on Tuesday, largely on a perception that the government is not doing enough to help workers suffering the effects of a crisis that others caused.

As the global economic crisis has driven companies to close sites and lay off workers, staff in France have taken to locking up managers to secure better terms for those losing their jobs.

Workers at the Caterpillar plant locked the site's director, head of human resources and two other managers in an office on Tuesday in a bid to force them back into negotiations over redundancy terms, a trade union official said.

A senior police officer negotiated on Tuesday a resumption of talks between unions and management at Caterpillar, but the management were not able to leave and spent the night there.

The head of Sony France was locked in an office overnight last month, and angry shop workers facing the sack blocked billionaire Francois-Henri Pinault in a taxi on Tuesday before riot police were called to clear away the protesters.

In his radio interview, Sarkozy also criticised German car parts maker Continental over its plans to cut a tyre manufacturing plant at Clairoix in northern France, which employs 1,120 workers. Managers there were pelted with eggs by angry staff last month.

The government has said the announcement of the site closure was not legal because the company's central works council was not notified. Continental contests this.

Sarkozy said he had discussed the issue with German Chancellor Angela Merkel.

"I said in Germany ... what I thought about their layoff plans. Those people are not above the law, so they should apply the law," Sarkozy said. (Reporting by Francois Murphy and Clement Dossin)