The European Union's high court has ruled that France erred in its ban on genetically altered corn, and has clarified the means by which member states can invoke a safeguard clause against cultivation of genetically modified organisms.

Monsanto sought review after France banned a type of genetically modified corn used in animal feed. The EU authorized the corn, which contains genes modified to combat a corn parasite, in 1998. The court ruled that cultivation of a GMO authorized as an existing product and pending renewal may not be suspended under a 2001 EU directive that applies to all GMOs, and France had used this directive for its ban. Member states may, however, invoke the safeguard clause under a 2003 directive related to GMOs for human or animal consumption, though this may be done only through a specific procedure, according to the court.

Member states must officially inform the European Commission as quickly as possible, the court's ruling said, and must establish a link between the GMO crop and "serious" risk, in a complete scientific evaluation involving the European Food Safety Authority. Such a risk assessment may be based on the precautionary principle.