(Updates with details of court ruling)
PARIS, Jan 15 (Reuters) - A French court cancelled the licence for one of Monsanto's glyphosate-based weedkillers on Tuesday over safety concerns, in the latest blow to the Bayer-owned business.
Germany's Bayer, which bought Monsanto for $63 billion last year, faces thousands of U.S. lawsuits by people who say its Roundup and Ranger Pro products caused their cancer.
A court in Lyon in southeast France ruled that the approval granted by French environment agency ANSES in 2017 for Roundup Pro 360 had failed to take into account potential health risks.
Bayer has cited regulatory rulings as well as scientific studies that found glyphosate to be safe and the firm is appealing a first U.S. court ruling that awarded $78 million in damages to a school groundskeeper from California.
Glyphosate, which is off-patent and marketed worldwide by dozens of other chemical groups including Syngenta and DowDuPont's Corteva Agriscience, is due to be phased out in France within three years under a pledge by President Emmanuel Macron, who stopped short of an outright ban.
The French court said ANSES had not respected a precautionary principle in French law, notably by not conducting a specific evaluation of health risks for Roundup Pro 360.
"Despite the European Union's approval of the active substance (glyphosate), the court considered that scientific studies and animal experiments showed Roundup Pro 360, a preparation whose toxicity is greater than that of glyphosate, is a potentially carcinogenic product for humans, suspected of being toxic for human reproduction and for aquatic organisms," the court said in a summary of its ruling.
Neither ANSES nor Bayer had immediate comment on the ruling.
"This is a great first, which must be repeated," Corinne Lepage, a former French environment minister and member of environment association CRIIGEN that brought the court case, said of the ruling on Twitter.
The association had also contested the process by which the EU renewed the general licence for glyphosate, seeking a referral to the European Court of Justice, but the French administrative court said such action was not necessary. (Reporting by Sudip Kar-Gupta and Gus Trompiz Editing by Ludwig Burger and Alexander Smith)