French President Emmanuel Macron opened the annual agricultural fair Saturday as angry farmers blew whistles and shouted insults.
Riot police kept the protesters at a safe distance as Macron toured the fair, tasting honey from Normandy and cheeses from the Alps, and shaking hands with exhibitors.
But as he entered the fair's livestock area, hundreds of protestors crashed the gates and clashed with police.
In the ensuing confusion, the fair was repeatedly closed and then re-opened to the public.
Police arrested three people for creating disturbances but they were later released, Paris prosecutors said.
In a separate incident, farmers poured manure on the stand of dairy giant Lactalis, which they accuse of not paying enough for its milk.
Farmers' leaders had warned Macron that his visit to the fair -- a fixture of the presidential calendar -- would not go smoothly if the government had not delivered on their promises to meet their demands.
He had begun the day at the fair with a two-hour meeting with the leaders of the three main farmers unions, the FNSEA, Jeunes Agricultures and Coordination Rurale.
Standing at plastic table, his jacket off and shirt sleeves rolled up, the president listened to complaints about prices, red tape and state aid.
It was a step down from the major national debate he had originally planned before scrapping it after a row over who could be invited.
"I always prefer dialogue to confrontation," Macron said. "I am telling you that work is being done on the ground, we are in the process of simplifying things."
The protesting farmers weren't impressed.
"Did you hear him? He doesn't let us speak, he talks down to us. We want him to go," farmer Eric Labarre, an FNSEA member, told AFP.
Macron said he would meet again with farmers in three weeks, after the fair shuts on March 3.