United States defense officials tell CNN that the Trump administration sought to reduce its contribution to about 16%, bringing it in line with Germany's, which provides 14.8% despite the U.S. having a larger economy.
But yesterday he said he was glad his recent comments have acted as a "wake-up call" and that it was "irresponsible" to just talk about financial and technical matters.
"If some people want to see an example of what they term "cost-sharing", they can come Monday to the ceremony France is organising" for the 13 soldiers killed in a midair helicopter collision while fighting insurgents in Mali, he said.
Merkel's statements come days ahead of NATO's 70th anniversary summit in London. Under the new formula, cost shares attributed to most European Allies and Canada will go up, while the United States share will come down.
In 2019, the U.S. contributed almost €470 million to NATO's budget of €2.12 billion.
Washington was previously the biggest contributor, paying about 22%.
At the December 3-4 summit in London, Trump is expected to repeat his demand that European nations and Canada increase their defense spending.
The assessment drew sharp criticism from allies, with NATO Secretary-General Jens Stoltenberg warning against undermining the transatlantic alliance.
Macron also took aim at NATO-member Turkey, saying its military offensive against Kurdish militia fighters in northern Syria "endangers the actions" of the coalition against the Islamic State extremist group - a coalition "of which North Atlantic Treaty Organisation is a member".
Turkish Foreign Minister Mevlut Cavusoglu has accused French President Emmanuel Macron of being a "sponsor of terrorism" after he critiqued Turkey's offensive in Syria against the Kurdish YPG militia.
The move followed the demise of the Cold War-era Intermediate-Range Nuclear Forces (INF) Treaty earlier this year that banned Russian Federation and the United States from deploying land-based, short- and intermediate-range nuclear weapons. "Let's be serious. We're talking about Europe's security".