It was formed after the 2015 Bremen state election by the Social Democratic Party (SPD) and Alliance 90/The Greens (GRÜNE).

The opposition CDU recorded a small improvement, and The Left made modest gains.

[1] Former state parliamentary leader Carsten Sieling, who was a member of the Bundestag at the time of the election, was nominated as his successor on 18 May.

[6] The congresses of both parties approved the coalition agreement on 11 June, with the SPD voting around 90% in favour and the Greens 85%.

[7] Carsten Sieling was elected Mayor by the Bürgerschaft on 15 July, winning 46 votes out of 82 cast.