“Despite the guarantee of free movement of people within the 26 countries of the Schengen area, some countries have introduced permanent border controls since 2015, Yves Pascouau, a senior adviser at the European Policy Centre (EPC) notes in a new study. Although border controls within Schengen cannot exceed a duration of two years, four-year old controls are now into place in Germany, Austria, France, Norway, Sweden and Denmark.”
See: Border controls ‘the norm’ in some EU states since 2015 (euobserver, link)
And: Border checks in EU countries challenge Schengen Agreement (DW, link):
“As large numbers of displaced people arrived in 2015, some Schengen countries reintroduced border checks. Six are extending controls. That’s illegal, EU observers say, and it undermines the idea of freedom of movement.”