It ain't too hard to find french cups-- I've multiple sets. The key is to stick the fixed cup on real, real tight. If it's a higher-end french frame, I'd be reluctant to mess with the BB threading. You could also try biketoolsetc.com -- they carry a YST BB for frames w/stripped threads, and at under 20$ they're cheaper than yours. Make sure the threading on any old cups marked 35x1 is French, not Swiss-- Swiss is the same pitch, but the fixed cup is reverse threaded.
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