The SIS II only contains the indispensable information (i.e. alert data) allowing the identification of a person or an object and the necessary action to be taken. In addition, according to the SIS II legal instruments, Member States shall exchange supplementary information related to the alert which is required for implementing certain provisions foreseen under the SIS II legal instruments, and for the SIS II to function properly, either on a bilateral or multilateral basis.
This structure built to deal with the exchange of supplementary information has been given the name ‘SIRENE’, which is an acronym of the definition of the structure in English: Supplementary Information REquest at the National Entries.
According to the SIS II legal instruments the supplementary information shall be exchanged in the following cases:
in order to allow Member States to consult or inform each other whilst entering an alert (e.g. when entering alerts for arrest);
following a hit in order to allow the appropriate action to be taken (e.g. matching an alert);
when the required action cannot be taken (e.g. adding a flag);
when dealing with the quality of SIS II data (e.g. when data has been unlawfully entered or is factually inaccurate);
when dealing with the compatibility and priority of alerts (e.g. when checking for multiple alerts);
when dealing with the exercise of the right of access.
This text is identical to the text in the Annex to Commission Decision 2008/333/EC (see page 4 of this Official Journal).