When Huret DuoPar and Success rear derailleurs first came out it took me a while to figure out what the 2 keyed washers were for that came in the box with them. There were no instructions covering those pieces.
I figured it out the first time I installed a DuoPar on a Campy dropout.
The black ones were for Campy style dropouts, the silver ones for the "batard" Huret dropouts! :-(
The black Campy style were easy to lose and pretty scarce too.
I just posted pictures of some of the solutions Huret used to mount their DuoPar, Success, Challenger plus the Eco versions and later Sachs-Huret derailleurs on industry standard dropouts.
There are probably more versions too, please chime in!
http://www.flickr.com/
The last picture shows an ingenious fix for mounting a Jubilee made for Huret dropouts on a Campy dropout. That type of adapter would probably work with the silver keyed washers too.
A while back there were some links to pictures showing the differences in Jubilees derailleurs so check the archives for that info.
Is it wrong, or just French?
Chas. Colerich
Oakland, CA USA