The European Food Safety Agency (EFSA) must disclose details of studies on the toxicity and carcinogenic properties of glyphosate, EU judges ruled.
Judges annulled two decisions by EFSA that denied access to details of the studies into the substance, which campaigners say should be banned. The two cases were brought by Greens members of the European Parliament among others.
"The public interest in having access to the information relating to emissions into the environment is specifically to know not only what is, or foreseeably will be, released into the environment, but also to understand the way in which the environment could be affected by the emissions in question," the European Court of Justice's General Court said in a statement.
Glyphosate was developed by Bayer's Monsanto under the brand Roundup. It is now off-patent and marketed worldwide by dozens of other chemical groups, including Dow Agrosciences and Germany's BASF.
In 2017, President Emmanuel Macron pledged to ban glyphosate in France within three years, rejecting a European Union decision to extend its use for five years.