Every city I have lived in has one area particularly attractive to amateur cyclists. London has Richmond Park, Seoul has the 한강, and Paris has le bois de bologne.
Until I have discovered better routes, for me Paris is the worst of the three for cyclists. Firstly the lap around the hippodrome doesn’t compare to the river cycle lanes in Seoul, nor is it as impressive as the Richmond Park loop. But it is still pretty and I think lots of club cyclists go there in packs.