Since 2015 there are Startup Weekends in Bremen:
Startup Weekend Bremen SPACE 2019
(covered by bremen-startups.de)
Startup Weekend Bremen WOMEN 2019
(Video 1)
Startup Weekend Bremen 2018
(Video)
Startup Weekend Bremen 2017
(covered by Weser-Kurier)
Founded after this weekend: Cup2date (taken over by ReCup in 2020)