@DC ATE:
You are with doubts that the flight had the required uplift of fuel including 3% Route Reserve. I would call this at least a big speculation, now I do not know what the ETOPS requirements of AF are (reserves may vary from operator to operator depending on certification of the authority envolved). But I am damn sure, that they had all legal requirements fulfilled.
Concerning Abnormal Airspeed Indication Procedure, I am Boeing driver, do not know much about Busses, but one thing catches my attention:
I cannot imagine that the high altitude cruising attitude of a bus is much different to other types. Makes my think that max 3,5° would be the value to start with and about 95% N1. Felt kinda uneasy people posting here that You go to 5° Pitch. You are at max altitude remember.
Reading a lot posts claiming problems at high altitude, I always tended and will go on so, to ignore too high levels in CFPs (company flight plans), never encountered any stability problem and at the end of my flights the fuel bill was not higher as if beeing flying the sometimes unrealistic high levels.