WTC tightrope docudrama ‘The Walk’ nails the landing

Robert Zemeckis’ “The Walk’’ reaches for the sky when aerialist Philippe Petit mounts a wire perilously stretched between the original World Trade Center towers, two-thirds of the way through this lighthearted docudrama, which makes great use of the 3-D IMAX format.

The trailers suggest a realistic thriller, not unlike “Man on Wire,’’ which covered much the same ground and won the 2008 Oscar for Best Documentary. But the family-friendly film, which had its world premiere Saturday night at the New York Film Festival, instead approaches history with a more fantastical and comic tone, not unlike Zemeckis’ “Forrest Gump.’’

Joseph Gordon-Levitt’s Pepé Le Pew-ish French accent takes getting used to, but he turns out to be an inspired choice to play Petit, a former Paris street mime who first gains public attention when he wire-walks between the towers of Notre Dame cathedral.

Gordon-Levitt’s comic chops and infectious likability help get you past what amounts to lengthy prologue about Petit’s obsession with wire-walking, which crystallizes when he sees a drawing of the WTC towers in a magazine.

With advice from a circus-aerialist mentor (Ben Kingsley) and emotional support from his girlfriend (Charlotte Le Bon), Petit arrives in 1974 New York. He smuggles suspicious gear through customs by joking about what he’s actually planning to do — and waltzes into one of the still-under-construction towers simply by donning a hardhat.

Atop the towers, a ragtag conspirator fires an arrow between the roofs so a 140-foot-long wire can be strung between them.

The film up to here is sometimes slow and occasionally corny — and doesn’t strictly follow the facts, something signaled by Petit’s abundant narration, delivered by Gordon-Levitt from the torch of the Statue of Liberty.

But Zemeckis finally delivers the goods in abundance in the section that ­really counts: A vertigo-inducing digital re-creation of Petit’s famous walk back and forth between the towers, 110 stories above street level. The tension is goosed a bit with Petit’s fantasies of what might go wrong.

In the end, “The Walk’’ finds a graceful way to pay tribute not only to Petit’s bravery and determination — but to the thousands lost on 9/11 in the buildings this daredevil loved so much.