You can take it with you
Martell is extremely talkative on this wall. Moreover they address us in English!
The target of this mural is the English tourist on the way back to his kingdom. Before the construction of the highway, all traffic to the Channel-ferries crossed Abbeville.
CLASS magazine (Issue of 30.VIII.2011: you'll leave this site; latest check XI.2015) says that the logo is inspired by the Swift, a swallow-like bird called Martinet in French. It was presumably considered the French word nearest to Martell which could be shown as a symbol.
Below the cognac is a second layer with another brand. The bottle reveals that it is the fancy Dubonnet.
The company has been founded by Richard Hennessy in 1765.
He was an Irish military man who had left his country eight years earlier. The logo must refer to this military past.