I'm sure the world is coming to its end in one way or another, but I'd like to point out that the prosecutor is just trying to execute his/her own prosecution (or part of it - charges against two defendants were dropped).
"Translated" into the discussion of this thread, this means that the prosecution continues to argue that (1) Concorde was defective and the accident could had been prevented if earlier incidents had led to modifications of the aircraft, and (2) the piece of metal on the runway was the "immediate" cause on the day of the accident.
Before getting into another round of discussion of this already discussed theory (and alternative views), I'd like to suggest to wait for the verdict (which, according to AFP, isn't expected before the end of this year).