Add-ons: it’s 3k to the Palais de Congrès, which also abuts Bois de Boulongne, and 4k to the Arc de Triomphe.
La Défense is Paris’ version of London’s Canary Wharf/Docklands. It’s a business-centric district of modern office buildings on the edge of town. It started in the 1970s but it is still growing. As with most things Paris, this area has been built on a grand, post-modernist scale. It’s pretty convenient — ~2 miles from the convention center. Running in this area is pretty good: long, wide plazas and pathways with trees, monuments, and places to shop and eat. Start at the Esplanade de Défense or anywhere in that vicinity, and continue along the Allée to the Grand Arch, which is a modern version of the Arc de Triomphe (note it is is a 5k straight shot from ‘Arc to Arche’). Note it’s a bit tricky connecting from the Arche into Nanterre, but a run into Parc André Malraux is worthwhile. There are ~2 miles of trails in here, including a couple of hills! On the return, pass by the “Cloud Towers”, and Rue Hoche leads to a bridge over the freeway and back into the La Defense area. There are good, business-y hotels in La Defense area.