You are absolutely right on every circumstance that the Korean word is faithful to the French pronunciation for Paris. (Having known that beforehand, in fact, this is why I came to the discussions to read about someone's question and then the answer.)
On a personal note, however, I would not like to refer to the English speakers as "pronouncing it wrong"; to me, that implies that the English language is spoken by merely the uneducated and that the Koreans are the ones with education (not that I prefer Koreans or anyone else for that matter to be uneducated, of course). Paris as an English word perhaps started off as a word that was faithful to its French and original standard and that later became anglicized to sound more English-like and less jargony. It just happens to be one of those words that are pronounced faithfully to a speaker's tongue and less conservatively, and the phenomenon to do so is quite common in other languages, so I am not easily surprised.
But do not take anything that I just said personally. Like all other opinions, this is designed to be debatable. What was said about the word Paris was correct and thus can be confirmed, and my thoughts are just thoughts. Oh, let us not forget the French liaisons, though not used in proper nouns.
Ri, because when it is at the beginning it makes a "R" sound, but, when it is at the end of a syllable it would be pronounced as "L" Please forgive me for not using Korean, I don't have a korean keyboard yet. If you need help with something you can always reply, or even better use more than one Korean learning website, other than duolingo, i suggest getting an alphbet learning one. Have a nice day! :)