Danish and Polish workers demand that Polish workers are paid the equal salary as the Danish workers. They are striking against the by the international consortium FLC.

Reportedly, hourly rates of the Polish workers are about three-fourths of that of Danish workers. Reportedly, Polish workers are paid 18,82 Euro per hour whereas the hourly salary for the Danish workers are 24,87 Euro per hour. Danish workers are striking for solidarity with the Polish ones.

https://www.welt.de/regionales/hamburg/article239640789/Fehmarnbelt-Tunnel-Jetzt-streiken-auf-daenischer-Seite-die-Arbeiter.html