Harvey is right about the problems, I bought one really cheap (I think $30) in the early 70's because the owner couldn't make it work. The worst problem was when my brother and I really stomped on the pedals, we actually stripped out the cotterpins in the rear drive side crank. We carried tubes, spokes, and cotterpins when we rode. I bought a Mel Pinto (same as a LeJune and Motobecane I think) and put nice stuff on it, what a revelation. Later I bought a Ritchey Skyliner and a Santana both are still in my stable.
I know working on the Gitane tandem led directly to me working at the Bike Shop. I had to become a master mechanic just to keep the darn thing running.
Oh well, those were the good old days