Complex sentence: Arras (;;) is the capital ("chef-lieu"/préfecture) of the Pas-de-Calais department, which is half of Nord-Pas-de-Calais, France's fourth most populous region.
Split into simpler sentences: Arras (;;) is the capital ("chef-lieu"/préfecture) of the Pas-de-Calais department. It is part of the Nord-Pas-de-Calais region, France's fourth most populous region.