I'm no lawyer, but I just wanted to make a quick comment about that:
Everybody, but especially this supposed magistrate could know that the French police had four investigators present at the forensic examination of the 51 victims in Brazil.
These experts were mandated by the judge in charge of the French
penal investigation. They are thus bound by professional secrecy (penal code, article 11) and cannot communicate directly any information to the BEA. If I'm not mistaken, only the French judge may decide to make their reports public.