It's Always Some Dam Thing
You probably already know that France is way ahead of most industrialized nations in replacing fossil-fuel power-generation sources with nuclear power (>75% of electrical production, good article here) and wind turbines (the charmingly named eoliennes). But the French were quick to jump on hydroelectric energy as well, back in the late 19th century.
One fairly early example of this is the dam on the flood-control canal diverted off the Rhone as it passes through Villeurbanne and Vaulx-en-Velin just upstream of Lyon. This dam is still in operation, and though it does not operate all of the time (depending on river levels) it still supplies most of the electricity needs for Villeurbanne.
As with everything else, the French took pains to ensure that aesthetics were just as important as functionality (in some cases more important; see "Citroen")
The dam isn't open to tourists, but there's a small shady square on the left bank that overlooks the facility, and an informational panel with various charts, blueprints, photos and diagrams, plus this groovy poster [photo] in which a sexily tousled Marianne unleashes the power of electricity for the mustachioed gent at lower right, who gazes in wonder at the works of man.
The old tow path alongside the canal remains, and can be used for an occasionally-rugged bike trip between Villeurbanne and La Grande Large, a sort of calm bay where the river widens and it suitable for use by various rowing and sailing clubs [photo].
Makes a nice spot for a waterside picnic as well, or just to take a breather before the return trip.