Macron made the comments on Thursday after a summit of countries that have been mulling the proposal.
"These reassurance forces are a French-British proposal," Macron said.
"It is desired by Ukraine and noted by several member states that have expressed their willingness to join. It is not unanimous. That is known. Besides, we do not need unanimity to achieve it."
Macron said French and UK military officials will work with Ukrainian counterparts to decide where the contingents could be deployed in Ukraine.
"These exchanges between military officials will define the locations, the number of troops so it is credible," he said.
"There will be a reassurance force with several European nations that will deploy."
Macron met Ukrainian President Volodymyr Zelenskiy and leaders from the so-called "coalition of the willing," a group of countries which are working to formulate a plan of support for Ukraine in the event of a peace deal with Russia.
The summit hosting the leaders of nearly 30 countries plus NATO and European Union chiefs comes at a crucial juncture in the more than three-year war, with intensifying diplomatic efforts to broker ceasefires, driven by pressure from US President Donald Trump to end the fighting.
But the conflict is raging on.
Before the leaders met in the French presidential palace, Russian drone attacks overnight wounded more than 20 people and heavy shelling on Thursday afternoon killed one person and knocked out electricity in parts of Kherson, Ukrainian officials said.
US-brokered agreements this week to safeguard shipping in the Black Sea and last week to halt long-range strikes on energy infrastructure were greeted as a first step toward peace.
But Ukraine and Russia have disagreed over the details and accused each other of deal violations, foreshadowing a long and contentious process ahead.
France and the UK are pushing a separate initiative to build a coalition of countries willing in one way or another to support the deployment of a European armed force in Ukraine, with the aim of securing any peace deal by dissuading Russia from attacking the country again.
UK Prime Minister Keir Starmer said on Thursday after the Paris meeting that Russia was stalling progress towards a peace deal.
"We agreed here in Paris today that it's clear the Russians are filibustering," Starmer told a press conference.
"They are playing games and playing for time," he said.
"I don't want to put a hard deadline on this but we need to see this developing in days and weeks, not months and months."
Starmer also said European allies would be ready to help put any peace deal into operation whatever its precise shape turns out to be.
He added that leaders at the meeting had "complete clarity that now is not the time for lifting of sanctions (against Russia), quite the contrary".
Italian Prime Minister Giorgia Meloni's office said the leaders talked about the United Nations playing a possible role in an eventual ceasefire deal.
"During the meeting, the leaders also discussed the importance of effective implementation and monitoring of the ceasefire, on which a possible UN role is emerging, in line with the Italian government's position," a statement said.
Ukraine and Russia have not hit each other's energy infrastructure since March 25, Ukraine's foreign ministry spokesman said on Thursday.
The US announced separate agreements with Ukraine and Russia on Tuesday to pause their strikes in the Black Sea and against each other's energy targets.
with Reuters
