With the Treaty of Amsterdam signed in 1997, Schengen was formally integrated into the framework of the European Union as a Schengen acquis. The Schengen acquis includes the 1985 Schengen Agreement, the 1990 Schengen Agreement and various decisions and agreements adopted during the implementation of Schengen. When the Treaty of Amsterdam entered into force in 1999, the decision-making power of Schengen rested with the EU Council of Ministers. Several Schengen countries – Belgium, Germany, Spain, France, Luxembourg, the Netherlands and Austria – signed an agreement known as Schengen III in May 2005. The agreement would create closer cooperation between countries in preventing and combating terrorism and crime. Relations between Iceland and Norway, of the one part, and Ireland and the United Kingdom, of the other part, as regards the areas of the Schengen acquis applicable to Iceland and Norway are governed by an Agreement approved by the Council of the European Union on 28 June 1999. The two Schengen agreements were a major breakthrough for transport in Europe. The queues were often a kilometre long, waiting for border patrols to signal them, but the agreements put an end to them. Now people can take into account neighboring countries without having to show any form of identity. Of course, airlines still require you to show it for security reasons, but border controls are much easier to navigate and, in some cases, don`t even exist. On the 14th. In June 1985, France, Germany, Belgium, Luxembourg and the Netherlands met near the small town of Schengen in Luxembourg to sign the Schengen Agreement.
The agreement provided for the abolition of all passport and other controls between participating countries and the establishment of a single external border. However, the provisions of the Agreement were not brought into force until a later date. At the time, the Schengen area was seen as a kind of laboratory testing the creation of a common passport area before extending Schengen to the whole of the EU. Although Switzerland is not part of the EU, due to its position at the heart of Europe, it has strong economic and social relations with many Schengen states and, together with Iceland, Norway and Liechtenstein (other non-EU states within the Schengen area), is part of the European Free Trade Association (EFTA). Switzerland became part of the Schengen area after concluding the agreement on the 26th. October 2004 and implementation began on December 12, 2008. Any person, regardless of nationality, may cross internal borders without being subject to border controls. However, the competent national authorities may also carry out police checks at internal borders and in border areas, provided that such checks are not equivalent to border checks. This applies in particular to cases where checks are not aimed at border controls and are based on general police information and experience. It shall also apply if the checks are carried out in a manner clearly different from systematic border controls and on the basis of random checks. In such circumstances, for example, the police may ask you to identify yourself or ask questions about your stay, depending on the purpose of the check.
For more information on police checks in internal border areas, see Cases C-188/10 (Melki) and C-278/12 (Adil). Originally, the Schengen Treaties and subsequent rules were officially independent of the EEC and its successor, the European Union (EU). In 1999, they were incorporated into European Union law by the Treaty of Amsterdam, which codified Schengen in EU law while providing opt-outs for Ireland and the United Kingdom, the latter providing for opt-outs since their exit from the EU. EU Member States that do not have an opt-out and have not yet joined the Schengen area are legally obliged to do so if they meet the technical requirements. .