The Ahmedabad Police registered the case in connection with the roadshow held in Bopal area.
"Hardik Patel, who heads the Patidar Anamat Andolan Samiti (PAAS), and his supporters were booked under section 188 of the Indian Penal Code for disobeying the police order," Bopal Police Inspector IH Gohil said.
Hardik Patel and his supporters, who were on their bikes, had organised a roadshow on December 11, despite being denied permission by the district authorities, he said. "Today, we have lodged an FIR against him and 50 other bikers for disobeying the police notification," Mr Gohil said.
This is the first police case against Hardik Patel after the state Assembly elections. Three days before the second phase of Gujarat Assembly elections, the rally-cum-roadshow on motorcycles and cars was organised, which started from Bopal and culminated at Nikol area on the outskirts of Ahmedabad, covering a distance of around 15 km.
While Bopal area falls under the jurisdiction of rural police, Nikol area is under the city police limits.
After the roadshow, Police Commissioner AK Singh had expressed displeasure over Mr Patel's move and said that legal action would be taken for holding the event without permission.
Mr Singh had denied permission to Prime Minister Narendra Modi and Congress chief Rahul Gandhi to hold roadshows in the city during the campaign which the leaders of the two parties had obeyed.