Having a river walk as beautiful as the Seine River through Paris must be motivating to those who want to stay in shape. Even in February, on a rainy morning, there were lots of people walking, running, or biking.
In addition, I saw something new this trip. Lots of little "pocket parks" have been created along the Seine where kids from 5 to 10 years old can play. In the one below, kids can practice their rock-climbing skills, with the rubberized surface below to protect them from injuries from falls.