A masked gunman armed with an assault rifle stormed into a sports club at around 1am on Saturday in the northern district of Estaque and shot dead a man in his thirties with a police record for dealing in drugs, Marseille prosecutor Xavier Tarabeux told AFP.
A 28-year-old bus driver who was in the line of fire was also killed. He was playing cards in the building and had no police record.
The deaths came 24 hours after Interior Minister Gerard Collomb visited the sprawling port city.
A total of 18 cartridges were found in the building, Tarabeux said.
A total of 11 people this year have been killed in Marseille in shootings related to criminal gangs. Last year, 14 people were killed in similar attacks in the Bouches-du-Rhone department, where Marseille is located.