just for you Tex-s:
"le Velo de Mercier" just means "the bike from Mercier" and it isn't a model designation at all.
Mercier bikes [even the more recent ones] didn't have names but numbers, you know like 100, 200, 300 - awlright!?
If it's from the seventies or early eighties and is all Campagnolo - BUY IT for heaven's sake! It's a good one.