Here's a link to a website, with a lot of nice pictures of the former u-boat pens in France. Historical and recent material. Just click on the pictures.
http://www.strijdbewijs.nl/uboot/hotspot.htm
The site is in dutch, and is part of a larger website with a lot of pictures and stories of WW II.
http://www.strijdbewijs.nl/
Enjoy, and if you don't understand the text, use an online translator! There's one in Internet Explorer. It's really worth it, and will give you hours of fun.