Paris Subway Stations with Character 3

I was very amused by the "for... keep going straight" signs in the Paris Metro. Instead of an arrow pointing up, they have an arrow pointing down. I think that's the first time I've seen that. I've only seen ones that point up. The first time I saw this sign, it took me a few seconds. I even instinctively looked for some place to go down. I remember my 10th grade English teacher told us an arguement she had with some French person about how to describe something in French. I'm not too sure what it was but I think it had something do to with describing something how deep the water level is. In English we say "20 meters below (the sea level)" and "20,000 leagues under the sea" while in French they use the word "above" as in the water is above the point of reference. I remembered thinking this was very intersting. My teacher said that she believes strongly that language (way of expression) gives you a lot of insight into a culture.