Apparently the Helicomatic hubs were a poor design and were prone to breaking spokes. My Peugeot thriftstore find had extra spokes taped to the seatpost... always a bad sign. Here's what Sheldon has to say about them...

"Some French bicycles (and many early Treks!) came with Maillard "Helicomatic" rear hubs. This was the first cluster that could be removed without a big powerful tool. They came with a cute little pocket-size tool that incorporated a spline wrench for the cassette lockring, a spoke wrench, and a bottle opener. The Helicomatic was a nice idea on paper, but poorly executed. These hubs are losers.

Both hub flanges were 1mm farther to the left than those of a normal hub, causing increased dish in the rear wheel, and persistent spoke breakage problems. Many loyal Helicomatic fans tout the ease with which the cassette may be removed for spoke replacement as a great virtue, but if the hub were better designed, it wouldn't break so many spokes!

These hubs were prone to bearing problems as well. Due to clearance requirements, they couldn't fit the normal 9 1/4" bearing balls, so they used 13 5/32" balls on the right side. These didn't hold up well. The cones tended to wear rapidly, and replacement cones are no longer available to fit these hubs."