Hi Willaume and Anbuva!
Willaume, thank you for giving me an example for those mails you mean!
I have tried to understand it, and I can't help judging it just too similar to spam-mails, sorry to say. Although I assume that this mail you copied for me is sent only to selected customers, it's an advertising e-mail, containing typical spam words as e.g. "gratuite", "garantie", "millions", "internautes", "vous", "pour", "choisissez" and "messagerie". I guess that's why the hash-value processed by the DCC Filter might be identical with other really spam, unfortunately. A possible solution for that problem could be a more detailed and extended text, describing the company more individually. Hope that helps.
Kind regards, Chactory