Simplify the following text for a Grade 7 native English-speaking person.
Original: Berck , sometimes referred to as Berck-sur-Mer , is a commune in the Pas-de-Calais department in northern France .
Simplified: Berck is a commune . It is found in the region Nord-Pas-de-Calais in the Pas-de-Calais department in the north of France .