Looking west (down river) with the bridge's central arch on the left.
This is one of the elevated sections of the Paris Métro transit system. It's the Number 6 line (Charles de Gaulle/Etoile-Nation) where it crosses the river on the Pont de Bir-Hakeim. The line uses rolling stock with pneumatic tires to reduce noise where the trains run on elevated track through residential neighborhoods. The views of the nearby Eiffel Tower (out of the photo to the left) are spectacular from the train as it crosses the river.
The bridge was completed in 1905, replacing an earlier bridge to accommodate the then-new métro crossing. Pedestrians and motor vehicles use the lower deck, while the métro runs on the upper level viaduct.