Hi Willow, no legal expertise as in your sphere; at best a layman (see pm).
However, sufficient experience in aviation, flying, testing and certification, and incident investigation - supporting formal investigations - to participate an abstract discussion from the aviation viewpoint.
My simple view of the legal position is that AF & Airbus are appealing the investigation finding, and subsequent court rulings and appeals which allow a prosecution to proceed - post #2, et al.
How can a manufacturer be held responsible for an aircraft which met all requirements, yet suffered a failure at a level of probability not considered by certification.
How might any differences between world aviation standards and local legal findings to be judged.
Similarly, how can an operator be held responsible for a situation (triple ADC malfunction and consequential system alerts) for which specific training was not required, and that training which was required had been approved by the regulator.
An adverse outcome, Manufacturer and/or Operator being held accountable for a situation, which previously met requirements of certification and training, would have detrimental effect for aviation and safety in general.