The French president, 39, launched the blistering attack on Mr Trump while speaking at a European Union summit on Friday.
He said: “Trump’s actions reinforce the need for unity and clarity” from the European Union.
Mr Macron said a united voice is important for international discussions about Iran and North Korea’s nuclear activities, and about Europe’s own defence programs.
He added that a “less-clear strategy from the United States” under Mr Trump has “catalysed” EU cooperation.
Leaders of EU member countries reaffirmed their support for the accord curbing Iran’s nuclear activities.
Mr Trump, 71, has denounced the Iran deal and escalated tensions with North Korea over its nuclear tests.
But the Frenchman said that he had not yet given up on convincing the US president to change his mind on some of his policies.
France has a vested interest in Iran.
The Renault car company recently entered into a multimillion-dollar automobile deal with Iran in August just after a new sanctions regime was approved by the US Congress.
Mr Trump reportedly told Mr Macron not to worry about the US sanctions adding “take all the money you can get” from Tehran.
He then boasted: “Actually, Emmanuel called up, and he talked to me. And I said, look, Emmanuel, they just gave Renault a lot of money. Take their money; enjoy yourselves.”
Adding: “You know, Iran is spending money in various countries. And I’ve always said it, and I say to them: Don’t do anything. Don’t worry about it. Take all the money you can get.”
The American and his French counterpart had appeared to get along when Mr Trump travelled to France on Bastille Day in July to meet Mr Macron and his wife Brigitte.
Mr Macron invited Mr Trump to be his guest of honour at the Bastille Day celebration, which featured French and American troops marching down the fabled Champs-Elysees in Paris.
The pair even turned heads with a white knuckled extended handshake that seemed to go on longer than it should.
And they enjoyed a “dinner between friends” and their wives at a Michelin-starred restaurant on the Eiffel Tower.
The French leader went so far as to say “nothing will ever separate us”, adding that Mr Trump’s presence was “the sign of a friendship across the ages” between their countries.
But, cracks began to show when Mr Trump pulled out of the Paris climate accord.
The landmark 2015 agreement was signed in the French capital and hailed a success as it made all countries reduce carbon emissions.
Mr Macron informed Mr Trump of his disappointment in the decision to withdraw from the deal.
Mr Trump fought back saying that the deal, brokered by his predecessor President Barack Obama, was bad for the US.
The odd couple are worlds apart in many ways with the 39-year-old French president being the youngest president elected in France, and the 71-year-old American the oldest elected in US history.
However, Mr Macron’s speech at the EU marks a change in tone towards the erratic US president.
Brian Hook, the State Department’s director of policy planning played down talk of a rift saying: “President Trump considers President Macron a very, very good friend.”