After months of protests across the country that saw farmers blocking roads with their tractors or dumping manure outside government offices, security was tight outside the venue, but no incidents were reported.
Inside, flag-waving representatives of farmers' unions were the first to greet the president, who spoke with them for some 20 minutes before going on to admire the fair's mascot, a Bazadais cow from southwestern France named Cerise (Cherry).
Hollande acknowledged that the crisis facing farmers is "exceptionally hard, exceptionally long, exceptionally generalised."
He added: "To come and exhibit in the context of so much difficulty and pain is a lovely act of patriotism. It is not compliments that farmers want but lasting policies."
Laurent Pinatel, spokesman of the national small farmers group Confederation Paysanne, told AFP earlier: "Agriculture is experiencing its worst crisis ever."
And the head of the main farmers union FNSEA, Xavier Beulin, said he would "remind (Hollande) of the depth of the crisis".
"There is a lot of worry on the farms, a lot of people are quitting (because) they feel there is no future," Pinatel said, noting that 5,000 farmers are leaving the sector each year.
The beef, pork and milk sectors have seen prices collapse because of declining sales to China and especially the Russian embargo on most Western food imports in retaliation for sanctions over the Ukraine crisis.
Grain and vegetable farmers are also feeling the pinch, especially wheat producers hit hard as world prices nosedive.
In addition, wholesalers, which have been engaged in a price war for several years, are demanding ever deeper cuts from suppliers, who are in turn squeezing farmers.
Meanwhile, a mild winter has upset the apple cart for many growers, who are bringing produce to the market before they can find buyers.
The Salon de l'Agriculture is a must on the calendar of any ambitious politician, and with an election just 15 months away, the glad-handing -- and the "stroking of cows' behinds" made virtually compulsory by the earthy president Jacques Chirac -- will be the order of the day.