The office of Tourism of Douarnenez is a good start for information on local attractions and cultural events in the region:

http://www.douarnenez-tourisme.com/

If you are looking for information about the maritime trades or businesses related to the sea. The Maritime Federation of the bay of Douarnenez is your best bet.

http://www.baie-de-douarnenez.fr/index.php

July 24 to 27th 2014 Douarnenez will host its bi-annual maritime festival Temps des Fête:

In 2012 they had a record 1200 boats participate in the festival with over 100,000 people attending more than 60 shows and programs throughought the three ports of Douarenenez & Treboul

http://www.tempsfete.com/

The municipality of Douarnenez is also a good resources for local events and attractions of interest as well as practical information about the city.

http://www.mairie-douarnenez.fr/index.php/cultureloisirs.html