Several police personnel were injured in the stone pelting, an official said, adding Chief Minister Vishnu Deo Sai was briefed on the situation by the chief secretary and the DGP.
Mandsaur, the epicentre of the agitation, has remained relatively peaceful even as farmer protests have spilled over to new areas of MP.
The scion of the erstwhile Gwalior dynasty garlanded the portrait of Mahatma Gandhi on the stage before sitting on the 'satyagraha'.
The MP CM failed to reach a compromise, even after launching a fast.
The road show was the virtual launch of the Congress campaign for the assembly polls slated later this year, in which his party has the tough task of dislodging the Bharatiya Janata Party, which has been ruling the state for the last 15 years.
Chouhan met some farmer leaders on Saturday, but failed to reach a compromise.