LYON, France (Reuters) - A decade-old lawsuit in which a French farmer with neurological problems accuses Monsanto of not providing adequate safety warnings for a weedkiller returns to court on Wednesday, adding to health claims faced by the Bayer-owned firm.

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Paul Francois, who says he fell ill after inhaling vapor from weedkiller Lasso in 2004, won rulings in 2012 and 2015 that found Monsanto liable for the intoxication, before France’s top court overturned those decisions and ordered a new hearing.

An appeal court in the southeastern French city of Lyon will hear arguments on Wednesday before giving its verdict at a later date.

Francois, who says he has suffered memory loss, headaches and stammering, blames Monsanto for not giving sufficient warnings on the product label.

“Maybe we’ll lose against Monsanto but the real victory for me is that I have converted my 200-hectare farm to organic production,” 55-year-old Francois told reporters before the hearing.

“This affair made me open my eyes and move towards a different kind of agriculture.”

Lasso was banned in France in 2007 after the product had already been withdrawn in some other countries.

Bayer said it did not wish to comment specifically on the case until the ruling in the latest proceedings.

But it added in an emailed statement that “the use of phytosanitary products does not pose any risk for human health when they are used according to the terms defined as part of the product authorization.”

Monsanto, acquired by Bayer last year, is also facing lawsuits in the United States over alleged cancer links to glyphosate-based weedkillers. Lasso used a different active substance to glyphosate.

Last year, the company was found to be liable for the terminal cancer of a school groundskeeper who had used glyphosate-based products.

It is appealing that verdict but faces another U.S. trial next month relating to a couple suffering from cancer.

In France, a court last month banned a version of Monsanto’s Roundup weedkiller range on safety concerns.

Controversy over glyphosate has been fueled by a 2015 conclusion from the World Health Organisation’s cancer agency that the substance was probably carcinogenic.

Glyphosate was originally developed by Monsanto but it is off-patent and marketed worldwide by dozens of other crop chemical makers.

After a heated European Union debate in 2017 that led to a five-year renewal for glyphosate’s license, President Emmanuel Macron said France would aim to phase out the weedkiller in three years.