The French president pulled back a promise from his predecessor to sell two thirds of shipyard STX in Saint-Nazaire.
Italian company Fincantieri was prepared to pay €79.5 million for the holding but it was whipped away by the young leader.
Mr Macron chose to nationalise the shipyard and offer a smaller 50-50 deal.
Rome was furious and Italian press began to slate the president, claiming backing him in Brussels was “a mistake”.
The nations were at a stand-off with both refusing to budge but as tempers flared France flew its finance minister Bruno Le Maire to Rome.
Despite claiming last week they had made Italy an “honest offer” which it should accept, each side emerged from the meeting saying a decision had been postponed.
Mr Macron and Italian Prime Minister Paolo Gentiloni will now meeet at a joint summit on September 27.
Italian Treasury Minister Pier Carlo Padoan said after meeting Le Maire: “It was decided that there will be time from now until September 27… to evaluate the chance to overcome these differences.”
Behind closed doors Macron is being urged to do the “European” thing – and make a decision based on god EU relations, not what is right for France.
In a joint statement after the meeting the pressure being piled on was made clear as Italy expressed “deep regret” at the French decision.
The two sides claimed they want to fulfil “their wish of facilitating the creation of a more efficient and competitive European shipbuilding industry”.
Just days ago, President of the European Parliament Antonio Tajani claimed in a strongly worded outburst there is no room for EU nations to look after their own interests.
He said: “The nationalisation of STX? This is not the way to give Europe industrial policy and industrial defence policy.
“The French government’s nationalisation of Saint-Nazaire certainly poses a general political problem: this is not the way to give Europe an industrial policy and an industrial defence policy.
“We need European champions and not national champions.”
France has now “commits not to open the capital of STX France to any third party and to consider Fincantieri as its preferred option for the future of the company”.
Mr Macron was expected by Brussels bigwigs to take the EU line but has undermined decisions taken by his neighbours, just months into his Presidency.
The French president’s meeting with a Libyan warlord and the president of the “unity” Government Fayez Seraj was also met with Italian fury.
Mr Macron vowed to open safer camps for migrants to stop them dying in the Mediterranean, despite Italy having already taken 100,000 this year and facing closed doors from other nations over burden sharing.
He was seen as trying to go it alone and play the hero – although Libya is ruled in parts by multiple militia – and any deal made in Paris was unlikely to work on the ground.