It is not outdated, I have heard about it, and we use it very often, here in Quebec.I seldom have seen it being used in English though, a lot of English words and expressions come from French, I suggest you to look into the history of the Norman Conquest and the consequences of it on the old English society; 30% of English words come from French and especially, Normand French. 

https://medium.com/@andreas_simons/the-english-language-is-a-lot-more-french-than-we-thought-heres-why-4db2db3542b3 ;