Macron has slipped seven points with just 36 percent of respondents having a positive view of the president who was elected on May 7.
Forty-nine percent have a negative view, a rise of 13 points, according to the poll for the Huffington Post and the CNews TV channel.
The poll of 1,003 people was carried out on July 26-27.
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It confirms a downward trend already shown by a previous poll, carried out by Ifop on July 17-22, which showed his popularity slipping 10 points in a month to 54 percent.
Macron, a centrist 39-year-old former banker, was elected with 66 percent of the vote, soundly beating far-right rival Marine Le Pen.
Macron's centrist government has announced 4.5 billion euros ($5.3 billion) in public spending cuts aimed at bringing France's budget deficit within EU limits.
In a frenetic first two and a half months in office, he has also hosted US President Donald Trump and Russian counterpart Vladimir Putin.
Jerome Fourquet, a political scientist from Ifop, said the polls showed the public was beginning to tire of Macron's slick communication style while he was slashing public spending.
“Some people are starting to get the feeling that he is an exceptional charmer and a communicator but whose Hollywood-like style of communicating is actually an instrument to bring in austerity policies,” he said.