Some 40 workers blocked access to management offices at the steel mill in Florange, in France's traditional industrial heartland of Lorraine, where two blast furnaces have been out of operation since last year due to lack of demand.

Management was due to announce a decision on the fate of the furnaces, which employ some 550 of the 2,800 workers at the Florange plant, after a meeting with unions at its French headquarters.

The rest of the plant is operational.

Socialist President Francois Hollande, who visited Florange while campaigning for the May presidential election, met the steelmaker's chief executive Lakshmi Mittal last week to ask him to either restart the furnaces or put the facility up for sale.

The daily Liberation reported that Mittal had given his "consent in principle" to finding a buyer, citing a source in the president's office.

Industry Minister Arnaud Montebourg said on Sunday the government was seeking contacts with leading steelmakers.

With French unemployment breaking the psychological barrier of 3 million for the first time since June 1999, the Lorraine region has been hard hit by a slump in industrial demand, particularly for the car sector, which has traditionally consumed much of Florange's output.

Frustration over Hollande's inability to stem job losses has taken a toll on his approval ratings, which have slid to as low as 43 percent in one survey.

(Reporting By Vincent Kessler and Gilbert Reilhac; Writing by Daniel Flynn; Editing by Kevin Liffey)

• A Permanent Economic Emergency