You either love or hate biscuits roses de Reims, (pink ladyfinger sponge biscuits), which have been doing the rounds since Maison Fossier perfected them in 1756 and swiftly became supplier to the king. Buy them here (a 100g box costs €2.50).
In the 19th century, it was the done thing to dunk them in Champagne, which was sweeter back then, and some still do today, though sommeliers might tut.