Surprised no-one's mentioned "sharp" yet ...
In France, the # symbol is always known as "dièse" - the musical term "sharp" - regardless of context. By the way, before Napoleon thought counting in tens would be easier, the French currency was Lsd, just like in Britain: Livre, sol or sou, et denier, with the same 12d to the s and 20s to the L. "Sou" persists to this day: je n'ai pas un sou - I have no money. And silk stockings are still measured in denier, though I leave it to someone else to explain the link.
Now, who still calls a slash a solidus?