Berck, sometimes referred to as Berck-sur-Mer in French or Berck-su-Mér in Picard, is a commune in the northern French department of Pas-d…Berck, sometimes referred to as Berck-sur-Mer in French or Berck-su-Mér in Picard, is a commune in the northern French department of Pas-de-Calais. Situated on the English Channel immediately north the mouth of the river Authie, Berck boasts over 11 kilometres of sandy beaches and grass-topped dunes, and since the middle of the 19th century it has been a destination for convalescents and vacationers.