When obtaining or providing a reference, essential traits of the applicant’s personality are assessed. According to the FADP, these are personality profiles. In order for such data to be processed at all, prior and explicit consent is required. This consent cannot therefore simply be assumed if, for example, the employee lists the previous employers in his or her CV. However, if the application documents contain information on a former employer or a former supervisor under the heading “References”, this may be interpreted as consent or approval to obtain references.
Source: FDPIC – Reference information in the application process