[[ Off-topic ! ]] The French and English traditions are rather alike, in this respect: very many places in the Dutch-speaking North were given a separate name in French (i.e. Temse => Tamise, Mechelen => Malines). A few of the bigger places in the South have a name in Dutch, too.
And then there's the places that were originally Dutch-speaking, but became French-speaking since - which is the case not only for historical Waterloo but also for the French cities of Lille ("Rijsel") and Dunkerque ("Duinkerke").