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.
In Old French, Paris would have been pronounced with a hard S. The English pronunciation is a result of the much longer contact we have had with France than Korea has.
English and French also use the same alphabet but different phonology, whereas Korean must transcribe the sounds completely.
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! :)
in this case, (파리), it's read as "ri", coz when an "ㄹ" meet vowels both before and after the "ㄹ", it reads as "R". If "ㄹ" meet a consonant either before or after, it reads as "L".
example (R): -아름→Areum -알았어→Arasseo -사람→Saram
Example (L) -알렉사→ Alexa -레인→Lane (lein) -살사→Salsa
Its depend on the word itself, if its an English word, like Duolingo = 듀오링고 so we say it (dyu.o.ling.go) But if its a korean word itself, then it depend on the word too, sometimes the foreigners often confused since they used ㄹ for both R and L... But not for the Korean, because they know the word and know how to pronounce it QwQ
The sound that the letter makes in Korean is neither an l or an r, it's sort of in between. This is why it's never good to rely on romanization (for example, "롤" can be romanized as either "lol" or "roll/role" and still be correct). There are a lot of good pronunciation guides on youtube that can help you with this. Here's one that's pretty good: https://www.youtube.com/watch?v=D-JeUA8dUkI
In French, the s is silent at the end. Since Hangul is phonetically consistent, they leave off the "s" sound so that it is said as close as possible to the original French name. As for the second part of your comment, I believe you are confusing "ㅂ," which is sort of in between "p" and "b," and "ㅍ," which is just "p."