A beekeeping cooperative in northern France has filed a legal complaint against Bayer after traces of the controversial herbicide active ingredient glyphosate were found in batches of honey.

Glyphosate is the key ingredient in Monsanto’s Roundup weed-killing program, used heavily in France. Reports said the apiarists filed the suit on June 7 to coincide with the closing of Monsanto's merger with Bayer.

The license for glyphosate to be marketed in the EU was approved by a narrow vote last November after a heated discussion in which France voted to end its registration. The country is now planning to ban use of the chemical on its soil within the next three years. 

According to a lawyer for the beekeepers, Emmanuel Ludot, the tainted honey charges came from a producer whose hives are near extensive fields of sunflowers, beets and rapeseed, where Roundup is heavily sprayed.

Ludot told French media he hopes the complaint will prompt an inquiry to determine the percentage of glyphosate in the batches and any health consequences it might have for humans.

Vincent Michaud, president of Familles Michaud, where the glyphosate-contaminated honey was found, told Agence France Presse (AFP) that "we regularly detect foreign substances, including glyphosate." If traces of the herbicide is found, the cooperative rejects the supplier's entire shipment.