What to visit in Paris?

I echo the suggestion to walk the city centre. Paris is designed to be a walking city and you can actually accomplish quite a bit in a single day. Of course you won't have much opportunity for depth, but you will gain a greater appreciation of the city and what you would like to spend more time on when you return! :)

One day in Paris? That's easy--take a bus tour (2 hours or so and English tours avail.). You'll see the Eiffel Tower and Arc de Triomphe. You can then decide which places you want to see the rest of the day. Or you can just go to the Eiffel Tower & Arc and spend an afternoon in the Louvre. There's a reason tourists go to these places-- beautiful, fun and lots to do. All I know about Brest is that during WW2, the Germans had a submarine base there and the concrete pens were more or less impenetrable. So the RAF bombed the city around the pens to try to choke off supplies to the Germans and 80% of the city was destroyed. I would imagine that some of the old submarine pens would be tourist attractions. Just yahoo Brest tourism and see what you get. If you only have a few hours, you would probably only have time to visit one place.