Lasne (Walloon: Lane) is a Walloon municipality located in the Belgian province of Walloon Brabant, to the south east of Brussels. On January 1, 2008 Lasne had a total population of 14,043. The total area is 47.22 km² which gives a population density of 297 inhabitants per km². Lasne is the richest commune in the country, measured by the average taxable income of the inhabitants. It also has the lowest local taxes of any commune in Belgium. The commune is twinned with Azay-le-Rideau (France) and Abbeville (USA).