By Agence France-Presse
"There are only losers in a trade war. With our EU partners, we will assess consequences on our industries and agree appropriate response," he tweeted.
Trump imposed the tariffs -- 25 percent on steel and 10 percent on aluminium -- despite repeated warnings from the EU and other allies that this could trigger a full-on trade war.
Last Friday, Le Maire warned that any such measures by the US would be "unacceptable" and called for a "strong, coordinated, united response from the EU".
The French minister then warned that the tariffs would have "a major impact on the European economy and on French companies such as Vallourec, ArcelorMittal and Ugitech".
"There are certain countries which practice dumping and other subsidies which distort global trade," he said, in an indirect reference to China. "The American authorities know that perfectly well, and it is this that they should be addressing, not anything else."
The White House said Thursday that countries concerned by the new tariffs could speak to the US in order to negotiate possible exemptions.
"The EU is a close ally of the US and we continue to think that the EU must be exempted from these measures," said EU Commissioner for Trade Cecilia Malmstrom.
"I will demand more clarity on this issue in the days to come," she added.