"Undeniably he is in contradiction with the commitments he had made," Le Pen said in an interview with France Info radio
. "I am coherent, I don't change my mind in a few days. He had said he would not be the policeman of the world, that he would be the president of the United States and would not be the policeman of the world, but it seems today that he has changed his mind."
Her comments come just two days after Trump hosted NATO Secretary General Jens Stoltenberg at the White House and declared that the military alliance is no longer outdated, which had been a frequent refrain of his during the 2016 campaign.
"I said it was obsolete," he said Wednesday. "It's no longer obsolete."
Le Pen, leader of The National Front, went on to say that while she does not know if Trump would continue to abandon his "America First" approach, she herself would stick to a France first approach if elected president.
"Will he persist, or is it a political coup which facilitates his domestic policy, I have absolutely no idea. But I am coherent in my analyses. When something favors France I say so, when it doesn't I say so too," she said.
Trump and Le Pen were seen as allies during the 2016 US presidential campaign. The two shared many nationalist policy stances on immigration and globalization. The French politician had said that Trump's presidential win "shows that people are taking their future back."
Le Pen's criticism comes as other nationalist politicians around the world have taken issue with Trump's recent policy changes
. Trump ally and pro-Brexit leader Nigel Farage said he was "very surprised" at Trump's decision to strike a Syrian airbase in retaliation for the regime's alleged chemical weapons attack against civilians.
Le Pen has been a strong critic of NATO during the French presidential campaign and has included pulling France back from NATO in her campaign platform. The leader of the National Front party, on track to make it through to the run-off election on May 7, has recently seen her momentum slowed.
"I consider that France does not have to submit to the calendar of the United States, so I want France to leave the integrated command of NATO," she said.