Note to parents strolling the High Line: Don’t let your kids look up.

The Meatpacking District’s newly opened, much-touted urban park along an elevated, former railroad trestle has unwittingly turned into a peep show near The Standard hotel, as randy hotel guests perform sex acts in front of floor-to-ceiling hotel windows.

Disgusted neighbors say they’ve seen men masturbating, professional porn films being shot and couples engaging in sex in full view of the stunning High Line park path running alongside.

“That crazy kind of behavior is completely unnecessary,” complained Bobby Shoule, 37, of Queens, the father of a 15-month-old daughter.

Business neighbors also are disgusted.

“I’ve seen a few porn shoots — three dudes walking around a hotel room with cameras and lights filming a couple,” said Joe, a manager at the next-door Brass Monkey. “I’ve seen at least 10 different people having sex. Saturday nights are the best time for the show.”

The Standard’s Facebook page bluntly encourages the explicit behavior.

“We encourage you to exercise your inner exhibitionist. Please share your intimate, and explicit photos with us — those floor to ceiling windows aren’t just for the views . . .”

The hotel Web site beckons:

“Whatever you do, just make sure the shots are HOT and that you get them to us in whichever way you can. It’s all about sex all the time, and you’re our star.”

After The Post contacted The Standard for comment, the posting was abruptly changed.

The 18-floor hotel opened at the end of last year — with raunch-friendly ads.

“We’ll put up with your banging if you put up with ours,” an ad declared, picturing a woman wearing nothing but a tool belt.

“We saw a naked girl jumping up and down on a trampoline right in front of the window,” said Shannon Brickner, who works at a boutique on West 13th Street.

“From the street, I saw a man and a woman. Everyone was looking up at them.

“They were facing outwards, and I could see their backsides pressed up against the window. I thought it was a photo shoot or porn.”

Complained a waitress at the Brass Monkey, “It’s a free porn show.

“You hear the cheering, then you look up and see naked people. You get some people that don’t realize. Then you get the real exhibitionists.”

Some unhappy passers-by were disgusted, too. “Recently, I saw a man masturbating in one of the windows,” said one person who asked not to be identified. “That’s when it left the funny side and moved to the gross, dark side.”

Grandparent Gwen Barrett said the neighborhood has always been edgy.

“That kind of stuff here is anticipated,” she said.

Still, “I definitely wouldn’t want to bring my grandkids here,” she added.

City Council Speaker Christine Quinn told The Post she hopes to bring the show to an end.

“The alleged actions of The Standard are unacceptable,” she said in a statement.

She said she planned to “follow up . . . to make sure they hear this message from the community.”

The Standard hotel did not returns calls for comment.

Additional reporting by Kevin Fasick and Jamie Schram