Very pretty! I totally understand the impulse to just go with it. ;)
The woman Mils thought was her mother (best explained in her CS) was quite the fan of France, so Mils learned the language, though I'd place good money on it being Parisian French that she speaks. That may make her a little shy about conversing, if Fleur speaks a different dialect (without even going into the background she has with the younger Weasleys or younger members of the Order!). I look forward to seeing what we can devise. :)