[lern_too_spel]

Paris is mostly flat. As long as you aren't racing to work, sweat shouldn't be an issue.

[seanmcdirmid]

Isn't La Defense on a hill? I remember the escalators going up to it and down from it, anyways.

[retinaros]

it is not flat at all

[lern_too_spel]

"Other than the hill of Montmartre and the Belleville area, the terrain of Paris changes less than the height of a ten story building."

Hence, mostly flat.