Sadly, as most tourist pass through Lyon, on their way from/to Paris, this beautiful town does not get the credit it deserves... But maybe that is also part of its authenticity as it is not as crammed with tourists...
The old town, the roman ruins, the huge Basilica perched atop the hill, the lively center, the intriguing "traboules" (tunnels through the blocks linking the old streets through superb medieval courtyards) are enough to spend a couple of days in the town.
What's more, some districts like The slopes are full of nooks and crannies where you can discover some alternative places which are a lot of fun to hang out at (boardgame cafes, chicha places...) and to be remembered : Lyon is the capital of gastronomy. In my eyes, one of 5 stops that must not be missed in France...
Paris is beautiful but it is not France, more like a tourist living museum.
Lyon is much more representative of France.