Hello, Pinkpanter...interesting that you would have asked this question. I hadn't thought of the phrase "bon viveur" for at least three decades until my girlfriend mentioned something about "bon vivant" tonight.
Suddenly, "bon viveur" popped into my head, probably from a high school vocabulary test. I had a little trouble finding it in both analog and online dictionaries, but here's an excerpt from a website that might clear things up (it certainly did for me).
bon viveur - the second word, is not used in French as such while in English it often takes the place of a fashionable man, a sophisticate, a man used to elegant ways, a man-about-town, in fact a bon vivant. In French a viveur is a rake or debauchee; bon does not come into it.
The French bon vivant is the usage for an epicure, a person who enjoys good food. Bonne vivante is not used.
Anyway, I hope this helps. (I realize you asked this question a couple of years ago, and may already have received too many answers.)
Good evening, and happy researching.