I'm not sure your argument for it being a French word is strong. In that case, half the words in the English language would not qualify. That, to me, is the beauty of the English language - the manner in which it has evolved and fearlessly adopted words from many other languages. But to classify 'compere' as rare is rather silly. 60 million Brits, 24 million Aussies, 5 million Kiwis (probably English-speaking people from the sub-continent and how many millions would that be?) all use the word freely and, I'd suggest, the majority of educated Americans are familiar with the word and probably use it on occasion.