French Foreign Minister Jean-Marc Ayrault | Roni Rekomaa/AFP via Getty Images France warns company about helping Trump build his wall ‘Companies also have social and environmental responsibilities,’ says French foreign minister.

The French government warned a construction company of the dangers of offering to help Donald Trump build his wall along the southern border of the United States.

Foreign Minister Jean-Marc Ayrault said French-Swiss construction giant LafargeHolcim "should reflect upon what its interests are. There are other clients who will be stunned by this," according to local media.

“Companies also have social and environmental responsibilities,” he added.

LafargeHolcim’s chief executive Eric Olsen has said he is prepared to supply the materials for the controversial wall along the border with Mexico, the building of which was one of Trump's main campaign pledges. "We are the number one cement group in the United States. We are here to support the construction and development of the country. We are not a political organization," Olsen said.

Earlier this week, it emerged that Trump's wall could cost as much as $21.6 billion, and take more than three years to construct.