“Paris Police Prefect Laurent Nunez says eight people were wounded, including two seriously injured,” Le Figaro newspaper reported.
Police detained six people during the event, three of them for assaulting government officials.
Earlier, dozens of tractors in Paris took to the streets to protest against government policies before the opening of the Salon of Agriculture.
Later, protesting farmers broke through the police cordon and entered the pavilion of the agricultural exhibition, where French President Emmanuel Macron arrived.
Macron promised to meet with farmers in the next three weeks.