I am looking for a phrase that is used occasionally in English as a near synonym of "expertise". For some reason, "coup d'mentarie" keeps going through my mind, but I don't believe this actually means anything at all and it doesn't produce any results on the web.
To clarify, I am looking for a word or phrase that sounds similar to this, whilst I am foggy about the language of origin and precise meaning. French is just a guess. :)