"Our destinies are linked," he said in a keynote speech on the future of Sino-French relations during a visit to the northern city of Xian, the starting point of the ancient Silk Road.
The USD 1 trillion infrastructure programme is billed as a modern revival of the ancient Silk Road that once carried fabrics, spices and a wealth of other goods in both directions.
Known in China as "One Belt, One Road", the plan will see gleaming new road and rail networks built through Central Asia and beyond, and new maritime routes stretching through the Indian Ocean and Red Sea.
The project has elicited both interest and anxiety, with some in Europe seeing it as Chinese expansionism.
While France had been cautious about the plan, Macron heartily endorsed the initiative.
"It represents a real opportunity to create bridges, through exchange, between countries and civilisations, just as the ancient silk routes once did," he said in an interview with the Chinese website China.org.cn.
"I think it's very important that Europe and China strengthen their collaboration on the initiative. France is ready to play a leading role in this."
But Macron warned that it should be carried out "within the framework of a balanced partnership" -- a reference to concerns about China's trade surpluses. France has a 30- billion-euro (USD 36 billion) trade deficit with China.
Macron's first official visit to Asia marks a new stage for his diplomacy, which has so far been concentrated on Europe and Africa.
He plans to seek a "strategic partnership" with Beijing on issues including terrorism.
In a French version of panda diplomacy, Macron will give Xi a horse as a gift: a retired Republican Guard horse that is currently in quarantine.
On climate change, Macron said he would talk to Xi about "relaunching the climate battle" by preparing an increase in their engagements to combat global warming at the COP 24 talks in Poland later this year.
"China kept its word," he said. "You demonstrate your immense sense of responsibility."
Cooperation will "show the world that the French and Chinese are capable of making our planet great and beautiful again", he said in Chinese.
After Xian, Macron will head to Beijing along with his delegation which includes some 60 business executives and representatives of institutions.
Human Rights Watch has urged Macron to call publicly for human rights improvements in China during his meeting with Xi, but the French president's office said the matter would be addressed privately.
Along with Brigitte, Macron visited the famous terracotta warriors in Xian, as well as a centuries-old Big Wild Goose Pagoda -- a Buddhist site -- and the city's mosque.
The 8,000-man clay army, crafted around 250 BC for the tomb of China's first emperor Qin Shihuang, is a symbol of ancient artistic and military sophistication in a country that proclaims itself a 5,000-year-old civilisation.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)