The discovery of a fifth victim at dawn on Wednesday came as angry local people accused Marseille officials of leaving the city's poorer residents living in risky housing.
French Interior Minister Christophe Castaner said five of the missing lived in the buildings and three were visiting.
The collapse has highlighted concerns over the condition of up to 6,000 buildings in Marseille, which have been estimated to be in similarly poor fix.
A spokesman for the Marseille fire brigade told CNN the cause of the collapses was unknown and that the search for missing survivors was continuing.
One of the fallen buildings was boarded-up, but possibly used by squatters, CNN reported.
Sabine Bernasconi, the local mayor for that area of Marseille, said one of the buildings had been subject to an evacuation order.
Three people have been found dead in the rubble of two collapsed buildings in the southern French city of Marseille.
Google Maps images taken in recent months showed the collapsed buildings had large cracks in their facades.
Local media reports said at least two passers-by were injured in the accident.
"We still have hope, even if that hope is fading". The disaster, he added, was "100 percent the fault of city hall". "It's hell here. and now people die for nothing", he said. Eight hours later, another neighboring building collapsed.
People had been living in nine of the 10 apartments at number 65, while a shop occupied the ground floor.
Recall that on 5 November it became known that two houses collapsed in Marseille. It was a dilapidated building but there were owners and tenants there.
But a 2015 government report said about 100,000 Marseille residents were living in housing that was risky to their health or security.
After searching the rubble through a second night, rescuers have retrieved the bodies of four men and two women, prosecutor Xavier Tarabeux told AFP.