As I understand it that is sorta true.
I believe that when pronounced with a correct French accent, there is kind of an inflection or hesitation after the pronunciation of the D sound and before the letter that follows it isn't there? That's the reason for the accent mark, right?
So while "Dee-Arc" isn't quite phonetically correct, "Dark", with no inflection after the D, isn't quite right either. There really isn't a way to type it phonetically correct in English without the ability to type all the accent and inflection marks.
I also believe that in French the "Bois" part of the name has a very soft "s" sound at the end (kind of a faint, breathy, "z" sound) that can't be correctly typed in normal English characters either. It would really be closer to "bwausz".
A french accent is pretty hard to type in English...