Macron and German chancellor Angela Merkel held talks on Monday before the negotiations continue at the next European council.
Angela Merkel has broad support in Germany for her handling of the COVID-19 pandemic, according to a Euronews poll. In France, fewer than half of respondents backed Emmanuel Macron's crisis response.
She has denied the allegations and said she would file a defamation claim.
The law allows for fines of up to €1.25 million but critics say it would curtail the democratic right to freedom of expression.
French President Emmanuel Macron, wearing a face mask, visited a school as the country prepares to ease its COVID-19 lockdown next week.
The Institut Pasteur estimated that 3.7 million people — 5.7% of the population — will have been infected with COVID-19 by May 11 but that 70% is needed for herd immunity.