Here we go again, but to answer briefly once more : the language to be spoken on the R/T is the language(s) stipulated in the AIP of teh country you are flying in. if in Geneva English and French is mentionned you can use either of them, like in many countries in the world like Montreal for instance.
Again,as someone said we are paid to obey the rules . Am I for changing the rules, yes, but until they are changed I have to follow them. So if I am, say in Paris, and an aircrfat call me in French, I answer in French, period.