That is the essence of the part of the current trial which is against AF : training . Reading the first (BEA) report one can see that they did not recognize the stall. Not only the PF but the 2 others as well, including the Captain at the beginning , only towards the end, he , and he alone , realized it but it was(far) too late.
One chapter in one of the reports, I forgot which one , goes in detail into the AF training syllabus, as far as I remember hands on training was concentrating on approach to stall, not on stall recovery. Those were the requirements of that time, although most airlines and AF in particular have changed that drastically since then. In addition against AF are their decision not to install /buy the BUSS, the late change of the Pitot sensors and some other small differences AF had compared to other airlines that were more pro-active in that respect. , That is what the Judges , lawyers and their experts are debating now.