well you're right, there's not a lot of info...you probably saw what CR has:
and if you search the archives (search.bikelist.org) you can find more chatter, but most is concerning the flagship model 300, which was Mercier's answer to the PX-10 and Gitane TdF. You find much more from these French makers (as well as Moto and Follis, even Stella) cause they sold more over a larger area in the States.
Coincidentally, there's a seller in Berkeley,CA who has a "his'n'hers" pair of Mercier 300s currently for sale on CL. The small "her's" is stripped and chrome-plated, around 52cm, and the "his" has original paint, around 56cm, both seem to be equipt with mostly original stuff, or period replacements, and reasonably priced too.