This is a rough plot of NASA SRTM (Shuttle Radar Topography Mission) altitude data for France, from west of Paris on the left to east of Strasbourg on the right. The river system that drains into the Seine is clearly visible: Paris is somewhere on the snaky black bits on the left. I made this plot to be certain I was interpreting the data properly, and the colour luminosity vs. altitude coding isn't perfect: generally, brighter=higher, but as altitude passes a certain value it recycles to black. I liked the pic, though, so here it is...