Supporters and opponents of the actor-turned-politician, popularly known as "Bihari Babu", clashed in front of the state BJP office on Bir Chand Patel Marg here.
Police said some members of the BJP Yuva Morcha shouted slogans against the candidature of Sinha from Patna Sahib and said they will oppose him and show him black flags.
Another group of BJP workers came out of the party office and beat up some of the protestors, a police official said.
Some BJP leaders said there was resentment among party workers after it fielded Sinha, who rarely visits the constituency.
"Not only party workers, the majority of people in Patna are not happy with Shatrughan Sinha," a BJP leader said.
Meanwhile, for the first time after he was declared the party candidate from Patna Sahib, Sinha along with his wife Poonam Sinha and his son Luv Sinha arrived in Patna Thursday.
He told the media there were no differences within the party over his candidature.
"I am thankful to the central party leadership and state party leadership for naming me as the candidate once again," he said.
Sinha's AAP rival is confident of defeating him from Patna Sahib seat
In another development, a day after the Aam Aadmi Party fielded her from Patna Sahib for the Lok Sabha polls, Perveen Amanullah said she was confident of defeating Sinha.
"I am fully confident and sure to win the polls from Patna Sahib," Amanullah told the media Thursday.
Amanullah, in her early 50s, said she was happy to take on Sinha, who hardly visits his constituency and has never bothered to spend time with the people to listen to their grievances.
"I am happy that the AAP has provided me an opportunity to contest from my hometown. I am a resident here. I am not missing from here like Shatrughan Sinha," she said.
Amanullah said people know what she has done for them.
"I have been doing work in different fields since 2002 here," she said.
Amanullah, the first woman Muslim minister in the state, recently resigned from the Nitish Kumar cabinet, quit the Janata Dal-United and joined the AAP.
She is the daughter of diplomat-turned-politician Syed Shahabuddin and wife of IAS officer Afzal Amanullah.
In the 2010 assembly polls, she had won from Sahebpur Kamal, a Muslim-dominated constituency in Begusarai district.