The body was one of the five to eight people identified as missing immediately after the incident on the city's Rue d'Aubagne, Marseille prosecutor Xavier Tarabeux said.
The buildings collapsed on Monday morning, and emergency services have been combing through the rubble.
Fire crews deliberately brought down an adjacent third building that was also in danger of collapse.
A man's body was pulled from the rubble on Tuesday morning and several hours later rescuers found a woman's body.
A completely flattened vehicle was dug out, an indication of the force with which the building came crashing down in what witnesses said was a matter of seconds.
"People died for nothing, even though we knew". "There could still be air pockets", a senior rescue official said.
Officials have vowed to inspect all buildings in the southern city deemed "unsuitable" for habitation, two days after the apartment blocks collapsed in a disaster rare for a major European city.
Images taken before the collapse show large cracks in the facade of number 63; a former resident, retired college lecturer Mark Mason, told the Guardian he had been forced to sell his flat in the building to the council in 2012 under a compulsory purchase order after the first storey floor collapsed and chunks of masonry began falling from the building. "It could have been me", she said.
Interior minister Christophe Castaner said eight people are missing from the building and that he was "not very optimistic" that they would be found.
"It could have been me", she added, visibly shaken.
The neighbourhood is home to many buildings in a similarly poor condition, some of them run by slum landlords. "It is the houses of poor people that collapse - and that is no coincidence", he was quoted as saying by local media.
The buildings were in a small shopping street in the centre of the city.
According 2015, about 100 thousand inhabitants of Marseille, live in housing that threatens their health or safety.