We model the behaviour of a buyer trying to evade the real estate transfer tax. We identify over-appraisal as a key, easily-observable element that is inversely related with tax evasion. We conclude that the tax authority could focus auditing efforts on low-appraisal transactions. We include ‘behavioural’ components (shame and stigma) allowing to introduce buyers’ (education) and societal (social capital) characteristics that explain individual and idiosyncratic variations.