The two men were pictured planting the tree together on the White House lawn in April past year during the first state visit of the Trump administration.
"Europe. must build new rules of trust and security with Russian Federation, and should not only agree with NATO", Macron said in an interview with the Swiss television channel RTS.
The tree, from Belleau Wood in France where nearly 2,000 American soldiers died in a World War One battle, had been dug up not long after it was planted.
"I won't speak for Angela Merkel", he said in an interview with Swiss TV station RTS, but added that "should she want it, I would support her".
A yellow spot is seen where the tree planted by French President Emmanuel Macron and U.S. President Donald Trump on April 23 stood on the South Lawn of the White House in Washington, U.S., April 28, 2018.
It was put into quarantine to prevent the possibility of parasites spreading to other trees in the White House grounds.
The oak tree was dug up and quarantined after the two leaders planted it as per American regulations, the French ambassador to the U.S. Gérard Araud confirmed at the time.
"We need to have a strategic debate, so this week I will have another, long and intense conversation with Vladimir Putin, as the president of France and the G7", Macron stressed. "There is disagreement among us, but we work together".
While Macron had a launched a charm offensive on President Trump following his 2016 election, the mood has since cooled.
Macron then praised leaders of the Second World War for setting up the United Nations after the conflict.
Since assuming the presidency of France, Macron has revived the ambitious plans of creating a combined EU military force - a real "European army" - to provide security for the continent.
'This promise of Normandy, we must find its essence once again to seize this commitment, what we owe to our homeland, to the alliance of countries with shared values, that of democracy and liberty'.