Guys,
I see your point, and you might certainly be right about national preferences for two equally qualified candidates.
But I have worked for Air France as Student Cabin Crew, and first their was foreigners in their crews (seldom but it was mostly due to the number of foreigners being totally fluent in French compared to foreigners speaking English for instance), and secondly Air France as an heavy company culture where French is just present everywhere.
If a foreigner is absolutely fluent in French and has a THE profile (the one Air France is looking), I am pretty sure, there will not be discrimination. But if you do not speak the language, it is just not compatible with the culture.
Do not forget we are talking about a FRENCH company, and if you guys want to work there in most areas, French is a must. Most of us are not even able to work in English...
Legacy airlines in Europe are not really international in their staff, so it makes sense to me, you must be proficient in the national language to be well integrated.