But there's a better railway walk in Paris, along a more impressive disused railway, and that's the Coulée Verte, or Promenade Plantée. Formerly the line to Vincennes, it was pedestrianised 25 years ago and has since become a much loved stroll. It starts near the Place de la Bastille and heads out east to the Peripherique, a total distance of almost three miles (which in London would be the equivalent of the Tower of London to Canary Wharf). I didn't manage the whole thing because I was tiring by then, but blimey the first half was impressive.
It doesn't look much to start with, a set of steps rising through a brick wall off the Rue de Lyon. But up top, heavens, it's something else. A linear garden, the width of a railway viaduct, deliberately landscaped as a path between cultivated beds. Normally the path runs along the centre, with plants to either side, but sometimes it splits in two around a raised planter, even a pond, before continuing. Pergolas and the occasional belvedere add to the variety, elevating the experience above your average green corridor.
At times bridges and buildings intrude, but more generally it's easy to forget you're several metres in the air on a brick viaduct above the streets of Paris. I completely missed that this section of the viaduct houses dozens of art studios, shops and boutiques in the arches underneath, as I enjoyed my uncommercial hike up top. Benches are provided at extremely regular intervals, generally south facing, making this a particularly popular place for older Parisians to enjoy. Basically it's a triumph, and all the better for having preceded New York's High Line by a decade and a half.
The approximate halfway point is Jardin de Reuilly (where the fizzy water fountain is), which the Coulée Verte crosses on a vaulting footbridge. Beyond that it returns to ground level, complete with bikes and public buildings, and then for variety's sake throws in a tunnel or two for good measure. The tunnels are a popular haunt for bats at dusk, and include cave-like projections and trickly fountains for added wow. I'd say there are are lessons here in spectacle and diversity that those making plans for a Camden or Peckham Highline would do well to learn from. But for sheer scale, and ambience, the Promenade Plantée is probably unbeatable.