Seven months from a presidential election in France, Alstom has become the focus of a political storm after it announced last week that thin order books were forcing it to halt manufacturing at the site where it made its first steam engine in the 1880s.

President Francois Hollande has urged Alstom, in which the state holds a 20 percent stake, not to go ahead with the plans, which would see production shifted to another plant in France while workers would be relocated to other French sites.

The government has set a 10-day deadline for a solution to be found in talks with Alstom. It has suggested that orders in the pipeline could be brought forward, by leaning on the SNCF state railway.

Alstom's four main unions said they would strike at sites across France and would protest outside the company's corporate headquarters in Paris's northern suburbs.

"The aim is to put pressure on Alstom's management and the state to find lasting solutions for the entire French railway industry going beyond Belfort," a CFE-CGC union official said.

The Belfort case has become politically sensitive as local politicians and critics accuse the government of knowing about the plans for the Belfort site before they were made public and doing nothing to save it.

"Clearly, the government knew everything, I regret they did nothing," said Arnaud Montebourg, a former industry minister who left Hollande's cabinet in 2014 and is now a Socialist presidential candidate.

Government spokesman Stephane Le Foll said on Wednesday that the state was aware of Alstom's difficulties but did not have advance warning about the Belfort announcement.

(Reporting by Cyril Altmeyer and Simon Carraud, writing by Leigh Thomas; editing by Richard Lough and Ralph Boulton)