Originally Posted by non-fixie

Top Tip: look for old rusty Gitanes in the classifieds. The Tour de France models (or Racing Team, as they were called in Europe - from 1974 anyway) had very short fork blades, which meant that only a short reach brake would fit. The odds are pretty good that if you find one, you've got your brakes.

BTW, and FWIW, when I rebuilt my own early seventies TdF many years ago I didn't have MAFAC's or other center-pull calipers that would fit, so I used Weinmann 605 side-pulls as placeholders. They're still there.