"so...does this mean that if I re-use the original cups, I can use a "5" sugino?"

Yes.

The races on the "5" spindles are slightly further apart, which allows them to fit in the narrower walled Euro cups. You can also hunt down an older Euro spindle; older Stronglights, some Campys, some TAs will work, Nervars may work, but then you may (or may not) find you have crank/spindle compatibility problems if you use a Japanese crank. On the other hand, you could just find one of those supercool Stronglight cranks with the Star shaped spider. But then you might get pedal thread issues, chainring replacement issues, and crank remover issues.

Weedeater, if the original cups are in good condition and you can work out the spindle problems, I say go for it, leave the original cups in. They are tanks and should last if maintained. You also avoid removal and installation problems. But the spindle compatability has always given me headaches; I prefer removing out the original cups and replacing 'em with the Japanese ones-- "3" spindles are easier to find, often with a nice old Sugino or Sakae crank attatched.

BTW, muccappazza, that TDF should be prime. What's the fixed cup, a Stronglight?

And remember-- French bicycles require a bit of patience when setting up. If someone came to me and wanted to build a bike to ride tommorrow, I wouldn't build them a French one. Sometimes it take a while to find the parts... and sometimes you run into odd stumbling blocks. One problem can seem to build into three more. But you come out the other end with a better appreciation for your bike and how it works. And they are nice rides. Very nice, in some cases.