French President Emmanuel Macron attends a meeting with local residents as part of the "Great National Debate" in Bourg-de-Peage near Valence, France, January 24, 2019. Macron visits the region as part of the "Great National Debate" designed to find ways to calm social unrest in the country. REUTERS/Emmanuel Foudrot/Pool

PARIS (Reuters) - It will not be possible to do without glyphosate-based weed killers in certain French agricultural sectors in three years because some sectors would not be able to survive economically, President Emmanuel Macron said on Thursday.

Macron has previously said glyphosate would be banned in France by 2020 apart from limited exemptions, rejecting a European Union decision to extend its use for five years after a heated debate over whether the Monsanto-developed weed-killer causes cancer.

The announcement of the ban caused an outcry among farmers who rely on it heavily, saying that three years was too soon to find an economic and environmentally viable alternative.

“We said ... we will do everything to get out in three years,” Macron said during a people’s debate in southeastern France. “Now, can we say there won’t be anymore glyphosate in three years? Impossible.

“I’m not going to lie to you, it’s not true,” he said. “Why, because if I did it, if I told you that, it’s simple, I’m completely killing some sectors.”