An item referred to the magazine
Marine Rundschau dated 8 August 1932 reporting that at Brest the keel laying of the Dunkerque of the dry dock was prepared. This manner of building was perhaps the reason for her length of just 200 metres against the 229 metres of the British battle cruisers.(1) This smaller length required a larger horsepower to achieve the desired speed but on the other hand her weight decreased due to less needed armour. The increased stability improved her seagoing qualities providing also a more stable gun platform. The French minister van navy announced that he had determined in building her. However was the building already delayed probably for political reasons.
Note
1. See for instance the links
http://warshipsresearch.blogspot.nl/2011/11/building-of-french-battle-cruiser.html and
http://warshipsresearch.blogspot.nl/2011/11/french-battleships-strasbourg-and.html