Well, I read the fic, and while there are serious indicators that this is a Suefic (first chapter is essentially a description of Miku and her backstory, she's a relative of a canon character, she "looks like a rebel" but is actually "sweet, nice, sometimes shy"), she's barely in the second chapter, so we don't know how the canon characters react to her. It's probaby a Suefic, but too early to spork.

I was able to translate some of it, and yes, it's very, very bad. The name is only the beginning. But really, I don't feel comfortable enough with my french to translate it all. I send out my prayers to anyone who attempts it.

It's really short, only two short chapters long, so there's not a lot to work with, but... well, here you go.

http://www.fanfiction.net/s/7330409/1/LaniecedeJohnWatson

My French is okay, so I might be able to decipher it. Alternately, you might be able to get an idea using Google Translate or something like that. Either way...the name definitely raises a red flag.

Miku... Miyazaki? ...I don't think that's a name you'd find in Sherlock Holmes... well, maybe unless she was a traveler from Japan, but I really doubt that...

I can't really help with the French, my knowledge of it is patchy at best, but... the name Miku Miyazaki is eerily similar to that of a character from a webcomic called the Order of the Stick - Miko Miyazaki. If you find someone who can help translate, letus know more? I know it's shaky evidence, but that just screams crossover.