"France should be on the offensive against pesticides," Royal told France 3 TV on Sunday, and that includes against pesticides in gardens, she went on.
Roundup, one of Monsanto's best-selling products, contains glyphosate.
The International Agency for Cancer Research in March declared that glyphosate was probably carcinogenic to humans, while acknowledging that the evidence was limited.
In a statement Monsanto said that it had received no notice of any ruling on the sale of Roundup, insisting that there was "no new scientific evidence" that might lead to a ban on its sale.
France's agency for industrial accident victims (Fnath) called for the government to act on the use of pesticides in agriculture, saying that it works with the "victims of these products".
Royal announced last week that from January 2018 phytosanitary products, which are used to control plant diseases, would only be available to amateur gardeners "through an intermediary or a certified vendor".