PARIS, France (CNN) -- Hundreds of French workers, angry about proposed layoffs at a Caterpillar factory, were holding executives of the company hostage Tuesday, a spokesman for the workers said. 

Caterpillar's French staff say they are angry about a lack of negotiations over layoffs. 

It is at least the third time this month that French workers threatened with cutbacks have blockaded managers in their offices to demand negotiations. Executives were released unharmed in both previous situations. 

The latest incident started Tuesday morning at the office of the construction equipment company in the southeastern city of Grenoble. 

The workers were angry that Caterpillar had proposed cutting more than 700 jobs and would not negotiate, said Nicolas Benoit, a spokesman for the workers' union. 

They did not want to harm the Caterpillar executives, Benoit told CNN. 

One hostage was released Tuesday evening leaving workers with four captives inside the Caterpillar building. 

The released man was a human resources director identified only as Mr. Petit, because he has heart problems, union representative Bernard Patrick told CNN. Petit had a heart attack a few weeks ago, Patrick said. 

The four others still being held are Nicolas Polutnik, the head of operations; two other executives; and Petit's personal assistant, he said. 

About 500 employees were also outside the building protesting. 

A top Caterpillar executive called the hostage-taking unhelpful. 

"The actions that are taking place today, led by a small minority of individuals, are not helping as we work for a positive resolution of this situation," said Chris Schena, Caterpillar vice president with responsibility for manufacturing operations in Europe, Africa and the Middle East, in a statement. 
Who was angry?
From what country?
Why were they angry?
How many people would be laid off?
Was the company willing to compromise?
What did they do to express their anger?
When?
Did they let anyone out?
Who?
Why?
How many others did they keep inside?
Were they trying to hurt them?
What city did this incident start in?
How many people were protesting in front of the building?
What was the company called?
Who is its vice president?
What does Bernard Patrick do?
Who did he speak to?
How many workers participated in the hostage situation?
Who is a spokesman for the workers' union?
workers
 Hundreds of French workers, angry about proposed layoffs at a Caterpillar factory,
France
 Hundreds of French workers
proposed layoffs
angry about proposed layoffs at a Caterpillar factory
more than 700
The workers were angry that Caterpillar had proposed cutting more than 700 jobs
no
The workers were angry that Caterpillar had proposed cutting more than 700 jobs and would not negotiate,
they held executives hostage
Hundreds of French workers, angry about proposed layoffs at a Caterpillar factory, were holding executives of the company hostage Tuesday, a spokesman for the workers said. 
Tuesday
 were holding executives of the company hostage Tuesday
yes
One hostage was released Tuesday evening
Mr. Petit
The released man was a human resources director identified only as Mr. Petit
he has heart problems
The released man was a human resources director identified only as Mr. Petit, because he has heart problems
four
The four others still being held
no
They did not want to harm the Caterpillar executives
Grenoble
started Tuesday morning at the office of the construction equipment company in the southeastern city of Grenoble.
About 500
About 500 employees were also outside the building protesting. 
Caterpillar
angry about proposed layoffs at a Caterpillar factory
Chris Schena
Chris Schena, Caterpillar vice president
union representative
union representative Bernard Patrick
CNN
 Bernard Patrick told CNN
Hundreds
 Hundreds of French workers,
Nicolas Benoit
 Nicolas Benoit, a spokesman for the workers' union. 