Wow this is a "don't miss" for me in Paris. The funicular takes you up or down the very steep…read morehillside to Sacre Couer at the top of Montmartre.
We had gone running to get to the top, then gone to mass at Sacre Couer, and just happened across the funicular walking downhill from the church. We took it down the hillside, but could see that it was far more popular going up from the crowd at the station at the bottom of the hill.
It's clean, well run and your Paris Metro card works at the gate. It's also great for people watching and views