BERLIN — German lawmakers opened the inaugural session of the new Parliament on Tuesday amid fears that the Alternative for Germany, the first far-right party to enter Parliament in decades, would focus more on confrontation than cooperation.

The party, known as the AfD, immediately made its presence felt by submitting a petition to challenge the order of business in a dispute over a change to rules that prevented one of its lawmakers from opening the session.

The move was swiftly rejected and — together with an attack against Chancellor Angela Merkel by her former governing partners — appeared to signal the end of the consensus style of politics that have dominated the past decade in Berlin.

“The people have decided, now a new era begins,” Bernd Baumann, who leads the Alternative for Germany’s parliamentary caucus, said in his opening remarks.