German engineering group Siemens is in the process of putting forward an offer for assets in French group Alstom, France's Economy Minister Arnaud Montebourg told parliament on Tuesday.
"An offer by German company Siemens is being presented," he told the National Assembly of lawmakers, signalling a counter bid by Siemens to thwart interest by US group General Electric.
Alstom builds power stations and the TGV high-speed train.
The minister reproached the head of Alstom, Patrick Kron, in strong terms for not informing the government of takeover talks with the US group, accusing him of deliberately keeping him in the dark.
Prime Minister Manuel Valls, in presenting his latest economic reforms to boost businesses before parliament, said that Alstom was "of national strategic importance".
The government would watch carefully over offers "and guarantees in terms of creating activity in France, the siting of decision-making centres, and for employment", he said.
And the government would be "extremely vigilant" regarding aspects of energy security, arising from Alstom's energy activities.
The fate of Alstom, suddenly put into play last week when the talks with GE emerged, is a highly sensitive political issue in France.
Earlier in the day, Montebourg told trade unions that the government would "do everything necessary to defend the interests of the state".