Sugino made French thread BB cups that worked with the standard 68mm spindle length. I picked some up from Harris Cyclery about a year ago for an UO8 I was working on. Looks like they're out of stock forever, but maybe ebay?
And yeah, you should replace the stem. I read that French steerers required a funky french-sized stem, but a standard quill stem slipped perfectly into my UO8.