Thanks a lot for the info about your exchange. It makes a lot of sense. However, I remember MtGox having a bank account in France (and AFAIK a license in Japan). So MtGox is doing illegal stuff?
According to MT the french bank account belongs to a company that simply forwards payments and bills the japanese legal entity 2% of the amount for this service, so I don't really think it's illegal at all.
Info about the french company is here
Looked it up a month ago didn't see anything weird, but as I'm looking today I notice the "Société radiée le 29/10/2008" mention, which basically means "closed since 29/10/2008". Really weird, I downloaded the associated legal documents, I'll find them and double check.
I'm going to talk with an international fiscalist in the coming weeks (next week a local Belgian one, later an international one). Maybe the exchange can be run from a VAT and tax free paradise somewhere (Belize, Antigua, ...)
That's not really a problem, the real problem is to get a bank in a respectable country to open you a bank account. If you incorporate in Belize, good luck finding a bank that'll open you a bank account in France, and if you open a bank account in Belize, good luck finding people that will accept to wire small amounts for huge banking fees, and good luck finding people that'll transfer large amounts to a tax haven using a bank wire (and don't care if they bring attention to them doing that.)
The problem is definitely non-trivial