The G7 club - comprising Britain, Canada, France, Germany, Italy, Japan and the United States - has also agreed to support a medium-term reforestation plan which will be unveiled at the UN in September, France's Emmanuel Macron and Chile's Sebastian Pinera said at the G7 summit in southwest France.
Brazil's former army officer president Bolsanaro has given freer rein to industrial farmers and loggers who have made the country an agribusiness power - at a huge cost to the environment.
Emmanuel Macron and Jair Bolsonaro have been involved in a spat after the French President criticised Mr Bolsonaro's handling of the Amazon rainforest fires and threatened to tear up a trade deal.
His remarks come amid an escalating war of words with his Brazilian counterpart Jair Bolsonaro, who he has accused of lying over Brazil's stance on climate change.
Bolsonaro replied on Facebook: "Do not humiliate the guy, ha ha".
Macron had tweeted an urgent message on Friday as the summit was just about to get underway, calling on fellow leaders to make the fires a priority of their meeting. "I hope they will soon have a president who is up to the task".
Brazil's powerful agriculture sector - which strongly supports Bolsonaro - has expressed concerns over the president's rhetoric, fearing boycotts of their products in key markets.
"We must respond to the call of the forest which is burning today in the Amazon", Macron said Monday.
The far-right populist leader initially dismissed the hundreds of blazes and then questioned whether activist groups might have started the fires in an effort to damage the credibility of his government, which has called for looser environmental regulations in the world's largest rainforest to spur development.
The comment quickly went viral in both the French and Brazilian press, with widespread criticism of Bolsonaro's remarks.
In July, Bolsonaro cancelled a meeting with French Foreign Minister Jean-Yves Le Drian - getting a haircut instead.
Disapproval of his personal performance as president surged to 53.7 per cent from 28.2 per cent, and approval fell to 41 per cent from 57.5 per cent, it said.
"August 2019 stands out because it has brought a noticeable increase in large, intense, and persistent fires burning along major roads in the central Brazilian Amazon", explained Douglas Morton, chief of the Biospheric Sciences Laboratory at NASA's Goddard Space Flight Center.
His worst actions to date, according to the poll, have been a decree easing gun controls, his offensive and inappropriate comments, spending cuts in education and the influence he has allowed his sons to have in his administration.
Meanwhile, thousands of people have demonstrated in cities across Brazil and outside Brazilian embassies around the world. Only 21.8 per cent though that it was his prerogative.