Durbuy, the smallest city on earth?

According to the signs, Durbuy should be the world's smallest city. Durbuy is a beautiful and small city, but to my knowledge it's not the smallest city in the world! The world's smallest city should be Bronkhorst near the river IJssel in the Dutch province of Gelderland. Bronkhorst, with it's 150 inhabitants, received it's municipal rights in 1482. However, Durbuy is a great place to spend some time, visiting all the shops in the narrow streets, lying down alongside the river Ourthe or viewing the castle.