Mexican Foreign Minister Luis Videgaray said the country will continue negotiating with the United States to revamp the North American Free Trade Agreement despite "unjust and unilateral" tariff measures by the USA government. These could come into force from June 20, although European Union officials said it might take a little longer.
Malmstrom is meeting U.S. Trade Representative Robert Lighthizer in Paris on Thursday among other worldwide trade chiefs.
"Finance Ministers and Central Bank Governors requested that the United States Secretary of the Treasury communicate their unanimous concern and disappointment", the group said in a summary statement written by Canada. The US, Canada and Mexico trade more than a trillion dollars in goods annually.
Officials from the three trading partners - among Washington's closest allies for decades - have dismissed the idea that their shipments to American customers endanger the United States - and some prominent Republicans attacked the tariffs as wrongheaded.
Canada and Mexico aren't immune from the tariffs either, and both countries have said they will retaliate.
And Macron pledged the retaliation would be "firm" and "proportionate" and in line with World Trade Organization rules.
Top European officials are holding last-ditch talks Wednesday with the USA commerce and trade chiefs just two days before the Trump administration decides whether to hit Europe with punishing new tariffs.
"This is stupid. It's counterproductive", former British trade minister Francis Maude told the BBC.
He said: "I think the proper reaction is first of all to say this is stupid, it's counterproductive, that any government that embarks on a protectionist path inflicts the most damage on itself".
For the European Union, a decision on just how far to push back will require agreement among the 28 member states that make up the world's biggest trade bloc.
Trump invoked a 1962 trade law to erect protections for USA steel and aluminium producers on national security grounds, amid a worldwide glut of both metals that is largely blamed on excess production in China.
USA tariffs on European steel and aluminum imports are expected after Trump administration's failure to win concessions from EU.
"That Canada could be considered a national-security threat to the United States is inconceivable".
All six of the other G-7 countries are paying the tariffs, which are largely aimed at curbing excess production in China.
The European Commission's president, Jean-Claude Juncker, said Trump's decision amounted to trade protectionism and that Europe would respond with countermeasures.
The EU earlier threatened to counter-punch by targeting USA products, including Kentucky bourbon, blue jeans and motorcycles.
"The announcement was made by Commerce Secretary Wilbur Ross and immediately it drew retaliatory action by Mexico, Canada and threats of the same by the European Union, while France calling the move as ïllegal".
Speaking separately after the meeting, frequently referred to as the "G-6 plus one", Mnuchin told reporters he was not part of the summary statement and said Trump was focused on "rebalancing our trade relationships".
Secretary Ross made it clear thta restructuring tariffs on USA goods is a high priority for the Trump administration. Trade Commissioner Cecilia Malmstrom added that the US, through months of negotiations, threatened steep tariffs in order to obtain trade concessions from the EU. The bloc plans to impose 25 percent tariffs on around 200 American products by June 20.
"As to Canada, Mexico, you will recall that the reason for the deferral had been pending the outcome of the NAFTA talks", he said. But the two sides could not reach an agreement.