What a wonderful world the internet can be. Someone on flickr has just pointed me in the direction of some information on this house. Apparently it has some history to it which can be found in the native French here...http://fr.blog.360.yahoo.com/blog-AkYRPIcjdKkVxo_LtoLzoQ--?cq=1&p=582
and a poor translation here
The house of the Father BRASSART (born in Hesdin in 1784 and died in Hesdin in 1854)
Louis-Joseph Brassart was the son of a merchant. He enlisted in the Great Army, and became a sergeant of grenadiers in the Imperial Guard. This unit participates in campaigns of Saxony in 1813 and France in 1814. The faithful old soldier follows the emperor in exile to Elba, he is at his side on his return to France during the Hundred Days. He was taken prisoner at the Battle of Waterloo. The father Brassart is appointed Knight of the Legion of Honor by imperial decree of 27 February 1815. Valiant soldier of the "old guard", he lives on his return to Hesdin in the former guardhouse at the door of Arras. Last guardian of the door before the disappearance of fortifications of the city, Brassart father died in this house of a military nature that exists today ...