The son-to-mother letter, sent to Normandy by balloon from a Paris beseiged by Prussians, was inexplicably found in Australia's National Archives.
French and US special forces helped Malian troops end siege in Bamako in which up to 27 people were killed.
Official says Abdelhamid Abaaoud not among 8 people arrested but that not all those who died in police raid had yet been identified.
Four UN contractors freed in raid, but Mali's UN peacekeeping operation MINUSMA said 5 people associated with mission had died.
The heist at the Champs Elysées Cartier store by armed robbers ended after they surrendered during a hostage siege near Montparnasse.
Police probe how taped exchanges between police and a jihadist gunman who killed seven people came to be broadcast on national television.
The 23-year-old suspected of killing seven people in France in the name of Al Qaeda died when police stormed his flat after a long siege.
The gunman suspected of shooting dead seven people said his only regret was not having been able to carry out his plans for more killings.