Uber from Paris Gare de Lyon?

It is not the worst station to pick up Ubers. There are two meeting points:
- right below "Hall 3", a dingy basement that is close to all tracks but not easy to find for the uninitiated
- In front of the Hotel Mercure to the left of the main exit. Close to the lettered tracks but 5-10 min walk from the numbered tracks.

This being said, regular taxis are usually plentiful, similarly priced and are typically faster within Paris (they can use bus lanes). I never use Uber or its competitors at the train stations.