Trim Stab :
That statement is most definitely not true. It would be illegal under EU law.
What would be illegal under EU ?
Do you mean the French regulations , i.e legal system , to be only in French ? I am afraid it is , and by law ( Loi Toubon ) and btw all the internal communication within the airline is only in French.
Same in Spain , I was recently part of a group having a conversation with the CEO of Vueling who tried unsuccessfully to have English as the legal language in his airline, but failed as any company registered in Spain, must use Spanish as its internal company language also by law.