The 28-year-old centre-back's deal was due to expire in 2015, but he has agreed terms on a fresh contract that runs until June 2017.
Lukimya was on target as Bremen started the new campaign with a comeback 2-2 draw at Hertha Berlin on Saturday and he was thrilled to be prolonging his stay.
"I sense a strong trust within the team and a high standing," he told Bremen's official website.
"I enjoy the calm way people work here and you can tell that things are going forward step by step.
"I am also happy to remain part of the team. My goal is to continue to develop together with the team."
General manager Thomas Eichin added: "Assani is a very important player who has a high standing within the team. Without a doubt, he is one of the league's strongest players in challenges.
"We are happy that Luki will stay with us beyond the season and that we can continue our road together."
Lukimya joined Werder from Fortuna Dusseldorf in 2012 and has gone on to make 46 Bundesliga appearances.