John Doe > Informal names for unknown or unspecified persons in various countries/regions Jean Dupont, Paul Martin, Monsieur Durand, Monsieur Untel/ Madame Unetelle, Monsieur/Madame X, Pierre-Paul-Jacques (even though those are three very common, typical distinct surnames, this is often said as a long uninterrupted string, as if an actual composed surname: "or" is added in the middle sometimes: "Pierre-Paul-ou-Jacques")
Languages French 100%, rapidly declining regional dialects and languages (Provencal, Breton, Alsatian, Corsican, Catalan, Basque, Flemish)