The study by the University of Paris on rats, was to determine what the lethal dose of C60 was. They discovered that high doses of C60 in olive oil is not lethal. Instead C60 prevented tumors and prolonged the life of the rats.

You mentioned theoretical studies mentioning C60 causes harm to DNA. The only reference I have seen is that carbon nanotubes can be harmful to DNA and cells because they are small and sharp. During the production process of C60, nanotubes and other forms of carbon are produced. These impurities have to be removed until only 99.99% pure C60 remains. That is one of the reasons that C60 is so expensive to produce.