i think they're a different diameter post - these brakes are copies of MAFAC which used proprietary braze-ons, PAUL use ordinary canti bosses, just in a different place.
Paul use proprietary braze one that both of its own mount are actually a different diameter to each other (literally, the left side is bigger than the right).
Compass use standard centerpull mount, which will work with mafac, shimano, gran compe etc.
i think they're a different diameter post - these brakes are copies of MAFAC which used proprietary braze-ons, PAUL use ordinary canti bosses, just in a different place.