Just for giggles, have a look at this -- I stumbled over this last night and, I have to admit, my eyes bugged out a little at a listing for a French bass under $4,000.
I called the shop owner, who informs me the bass has a plywood flat back and bears the label "Humbert." He is, of course, positive it's French circa 1900.
http://zaretandsonsviolins.com/basse...stic-bass-1900