Free movement of people in the Schengen area is one of the most important and tangible results of the EU integration process. It is ensured and maintained because of two crucial cornerstones: solidarity (to share the burden that weighs particularly on the shoulders of the countries along the Schengen external border) and mutual trust (so that one Member State has confidence in the checks carried out by the other Member States).
The Schengen Agreement was signed in 1985. Today the Schengen family consists of 28 countries and there are already further countries ready for full accession. To deal with Schengen matters there is a specific Working Party in the Council, which can meet in four different configurations: Schengen Evaluation, Schengen Acquis, SIS/SIRENE and SIS-Technologies (SIS-TECH).
■ SCHENGEN EVALUATION
To make sure that countries wishing to join the Schengen area of free movement properly apply the "Schengen acquis" and to ensure that the acquis is being properly applied in countries already part of Schengen, a 'Standing Committee on the evaluation and implementation of Schengen' was set up in 1998 and integrated into the EU framework in 1999 by the Treaty of Amsterdam. Ever since then, evaluation committees made up of Schengen Member State experts, accompanied by a Commission and a GSC representative, carry out regular evaluation visits to check whether the acquisis applied properly in the following fields:
- Border control (at air, sea and land borders),
- Cross-border police cooperation,
- Data Protection,
- SIS-SIRENE functioning,
- Visa issuance (Consulates).
Besides identifying difficulties and shortcomings, the expert teams make recommendations and proposals for improvements with a view to optimizing the application of the Schengen Acquis and the cooperation between Member States and identify - where possible- best practices in the way the acquis is implemented.
All this finds its way into evaluation reports which are then discussed and adopted in the Working Party for Schengen Matters - Schengen Evaluation.
"Protecting a Europe
without internal borders"
SIRENE stands for Supplementary Information Request at the National Entry and outlines the main task of the "SIRENE Bureaux" established in all Schengen States, which is the exchange of additional or supplementary information on alerts between the states.
SIRENE Bureaux are national coordination offices in the participating countries that provide supplementary information on alerts and coordinate measures in relation to alerts in the Schengen Information System (SIS). They also ensure that appropriate action is taken if a wanted person is arrested, a person who has been refused entry to the Schengen area tries to re-enter, a missing person found, a stolen car or ID document seized, etc.
SIRENE Bureaux also exchange data important for police and judicial co-operation, conduct database queries, coordinate cross-border operations, etc.
■ SCHENGEN INFORMATION SYSTEM - SIS
The SIS is a common database on persons and objects. The SIS is used by police, the border and migration and law enforcement authorities of the participating countries. It can be accessed (subject to strict data protection rules) at the borders, inside national territory and abroad, in consulates.
As of 1 January 2013, the SIS contained more than 46 million entries, concerning persons (around 1 million) and lost or stolen objects (around 45 million), for seizure or use as evidence in criminal proceedings
On 9 of April 2013 a second generation Schengen Information System ("SIS II") which provides additional and enhanced functionalities came into operation.
The information is organised as alerts, an alert being a set of data enabling authorities to identify people or objects with a view to taking appropriate action. The system is used by police, border guards, customs officers, and visa and law enforcement authorities throughout the Schengen area.
SIS II makes it possible to enter a copy of a European Arrest Warrant and to make links between alerts. There is also the possibility to store a greater range of objects including boats, aircrafts, credit cards and industrial equipment.
SIS II contains also photographs and fingerprints. Initially they will be used only to confirm the identity of a person; if and when the technology is available, it could then become also possible to search for a person's identity based on fingerprints.
SIS II  is in operation in 24 EU Member States as well as in the four non-EU countries which are associated with Schengen cooperation: Norway, Iceland, Switzerland and Liechtenstein.
 Relevant legislation on SIS II: Regulation (EU) No 1986/2006, Regulation (EU) No 1987/2006, Decision 2007/533/JHA, Decision 2013/115/EU, Decision 2013/157/EU and Decision 2013/158/EU.