BTW the Perron, ancient symbol of the liberties of the City of Liege, is shown among the Liege proofmarks. The word "Perron" comes from pierre = stone in French. It is also shown in the coat of arms of liege.

The perron proper was composed in the early middle ages from Roman artifacts, some marble slabs, a pillar, four lions and a pineapple. Lions and pineapple were Roman gravemarkers.
The photo shows what the real thing looks like, standing on a 17th century substructure in the Liege marketplace.