Personal data processing for behavioural targeting: which legal basis?

The European Union Charter of Fundamental Rights only allows personal data processing if a data controller has a legal basis for the processing. This paper argues that, in most circumstances, the only available legal basis for the processing of personal data for behavioural targeting is the data subject's unambiguous consent. Furthermore, the paper argues that the cookie consent requirement from the e-Privacy Directive does not provide a legal basis for the processing of personal data. Therefore, even if companies could use an opt-out system to comply with the e-Privacy Directive's consent requirement for using a tracking cookie, they would generally have to obtain the data subject's unambiguous consent if they process personal data for behavioural targeting.